PERHAPS THE worst mistake one can make before going to an Italian film is to skip dinner. The characters on the screen are bound to settle down to at least one mouth-watering repast and possibly several. You become so hungry, you can't follow the plot.

Art, as we all know, imitates life. The worst mistake one can make before going to Italy is to decide to skip meals. Unless you cloister yourself in an art gallery, you are going to become hungry -- very hungry. Eating is an Italian national passion, and food is virtually everywhere. The smell of coffee greets you in the morning in Venice. In Florence, seeing a person carrying an ice cream cone is as commonplace as spotting a Londoner with an umbrella. In any city or large town, you stumble across open-air markets selling fresh produce and little cafes with displays of tempting small sandwiches. Restaurants and food shops with inviting window displays line the streets.

It was easy on a recent tour through Northern Italy to form the impression that, work aside, city people only eat and shop, and country people only eat. Dining in Italy has very little to do with Italian dining in America, however. Anyone who steps into a restaurant should be willing:

To eat several courses. (Don't worry, though. Your first course pasta won't reappear beside your veal cutlet. Pasta is a course in and of itself. Also, splitting portions or skipping courses in Italy puts no one's nose out of joint.)

To eat earlier and in a shorter period of time than you would in Southern Italy, France or Spain.

To stand up before ordering and inspect the trays of uncooked fish and vegetables. Guide the waiter by pointing, if communication breaks down, to your choices from the trays and the antipasto (appetizer) display.

To order regional specialities and wines. To experience the full flavor of Italy, it is necessary to broaden your horizons beyond spaghetti to other forms of pasta, beyond shrimp to other shelfish and beyond veal scallopini to other cuts and other meats.

Before all this, of course, it is necessary to select the restaurant. As with so many things in Italy, the choice is at once very simple (because there are so many restaurants) and very difficult (because Italian restaurants are congenitally inconsistent). Not only does food quality vary from day to day, but often the chef will do one form of cooking -- say roasting meat -- very well and pay scant attention to perfecting the rest of the menu.

That being said, it is difficult to eat really badly -- in the sense one eats badly in the United States. Even the cafeteria in the Milan central train station offered fresh-tasting soup, al dente pasta and tender roast veal. Everywhere, the raw materials are fresh and in many recipes very little is done to them. Bread, fruit and coffee range only from superb to excellent. The cautious diner can order a meal course by course. If things don't go well with the antipasto or the pasta, cut your losses and stop. There will be another place nearby for a rich dessert and coffee, or just wait. The next meal never is far away, either.

The most talked about guide to restaurants isn't even Italian. It is the red book prepared by Michelin Tire Company of France. Italians inevitably clinch their teeth when asked about the Michelin. Not one restaurant in all Italy is considered worthy of the Guide's top, three-star, ranking. Perhaps a dozen, at most, have two. You needn't share the Italians' chauvanistic anger. The Michelin is very helpful to a foreign traveler. I asked a Venetian food expert for advice on that city's restaurants. He suggested five. I found all five listed in the Michelin, though not necessarily with stars.

But the Michelin's goal is to aid French people to travel without feeling they have left France. Casualness and informality offend the French culinary bible almost as much as does an absence of sauces. As simplicity is one of the cardinal virtues of Italian (as opposed to Italian-continental) cooking, a great many modest but worthwhile restaurants are not in the Michelin. One way to find them is to ask natives -- hotel personnel, shopkeepers and taxi drivers. There is some risk, but Italy may well have the lowest ratio of tourist trap restaurants in all Europe.

Piedmont, the region that keeps Milan from being in France, has absorbed a good deal of the gastronomic finesse of that country without sacrificing its individuality. The region is dotted with one-star Michelin choices and there are two-star restaurants in Turin and Costiglione d'Asti. The latter, called Guido, has the enthusiastic recommendation of knowledgeable friends. No one is seated without reservation, and the menu and wines are chosen by the owner.

We were further south, in Alba. Fresh truffles and porcini mushrooms, the most famous local specialities, were in season and couldn't be better further from the source. In the town, the best choice is Da Beppe. The modern decor and colors are slightly out of focus, but the food is traditional and good. Pasta in veal stock, risotto with mushrooms, anything with fontina cheese and a selection of boiled meats (bolitto misto) with an unusual green sauce are not to be ignored. Francesco Beppe, who commands the dining room, has a fine knowledge of local wines such as Barolo, Dolcetto and others, and a superb grappa (brandy).

At the highest point in the Barolo wine area nearby is a little-used hotel which houses a very popular restaurant. At midday the huge dining room of The Belvedere attracts tourists by the busload. Unless they have filled the place to the point no table is available, the crowds should in no way deter you. Seasonal regional specialities are featured, and the cooking is of a very high level.

Turin is justly famous for its chocolate (giandudjoni or the tiny gianduitto) and bread sticks. At the Cafe Torino, at the heart of town on the Piazza San Carlo, you will find excellent sandwiches and what may be the world's best hot chocolate drink. The historic Del Cambio restaurant has a wonderfully stylized dining room (a trio of chandeliers, cherubs smiling from the walls, mirrors and floor-to-ceiling curtains). Sadly, with such a setting the staff and chefs appear to think they are part of a long-run drawing room comedy. The food isn't bad but freshness and imagination are lacking.

Del Cambio rates one star in Michelin. The 12 Apostles in Verona rates two, though not across the board. The setting is a charming impressionistic version of a medieval chapel. There are rolling carts for antipasto, daily specials, desserts and a magnificent salmon baked in an equally magnificant pastry crust. The house Soave is fine, and prices on the wine list are not out of line. Among the cold antipasti, tiny artichokes and goats' milk cheeses stood out, as did mussels and mackerel. Among hot dishes, a black olive sauce on spaghetti was superb, and a layered creation of eggplant, tomatoes, peppers and bread was good and might have been even better if it was warm instead of tepid.

A mixed grill produced mixed results, although it came with very good polenta (about the nicest thing that can happen to corn meal mush), and veal scaloppini was far from tender. Very good rolls and cooked fruit or Italian-style trifle for dessert plus a complementary glass of sweet Valpolicello.

In Venice, someone suggested the best routine is to eat at Harry's Bar, buy food from the market and skip the rest. They were wrong. Harry's Bar is a world-class restaurant with world-class prices. Go. Try fish or liver or lamb, or the giant club snadwich. Portions are large, but don't resist dessert, particularly the chocolate cake.But there is plenty to eat elsewhere. In Venice concentrate on fish, either grilled or fried or in soups. You might enjoy the informality of the Conte Pescador, which offers a fine seafood antipasto that includes lovely, sweet tasting squid eggs, as well as a mixed grill of fish. The Antica Cavana, north of the Rialto Bridge, does a good job with vegetables and pasta and serves a fine version of squid in its own ink. The wines from Friuli, particularly pinot grigio, sauvignon, cbernet and merlot, are worth seeking out. Contrary to the popular notion, I found the bottled wines distinctly superior to those served in pitchers.

In Bologna, often called the dining capital of Italy, there was time for only one restaurant meal. Palmirani is a modern-style restaurant in decor, but such is the commitment to cooking in this town that the kitchen -- simple and old-fashioned -- open to view. Meat sauce, as identified with Bologna in Italy as is "bologna" in the United States, is rough-cut, not ground, and applied in modest quantity. The pasta is not very thin and slightly chewy. Bread is served in the shape of a starfish. Another local specialty is bolitto misto. At Palmirani the meats are beef, tongue, wonderful sausage and hog jowl. The green sauce here is really a compote of minced vegetables -- including leek and carrot -- with oil. rThe wine to drink with this dish is lambrusco. On its native ground lambrusco is dry, not vaguely sweet as it is in this country. The soft fizz does help cut the richness of the meats and sauce, but it is not a wine I would seek out, dry or sweet.

In Florence, there was a rainy-day lunch in Mama Gina, a crowded, brightly lit restaurant of three rooms. It is popular with tourists, and, like most Italian restaurants, polite and patient with them. The tagliatelle fiorentina and vegetable soup were commendable, as were slices of roast veal. The potatoes with it were reheated and tough, however, a common failing. Side orders of spinach and green beans were all one could expect Even more in the case of the spinach) and large steaks were being praised at the next table. I tried a most unusual mixed grill: fried brains, porcini mushroom, potatoes, zucchini and a chicken croquette. Strange but nice. The wine: a fine 1974 Chianti Classico.

In general, prices for restaurant meals in Italy remain fairly reasonable and, in comparison with hotel rates, are a bargain. The best meal of the trip, however, wasn't in a restaurant. It was at the home of a winemaker in the small village of Pancole.

From the window vineyards stretched away toward the distant towers of San Gimignano. The meal began with proscuitto from the farm and from Parma plus some superb salami. Next came a mushroom risotto, followed by a mixed grill of veal, steak, magnificent homemade sausage and pheasant that our host had shot himself. The wines were his vernaccia and chianti. Salad, cheese and a regional layer cake called mandarlotto brought the meal to a conclusion, made dinner that evening unnecessary and offered final proof that in Italy home cooking is the best cooking. Vermicelli with garlic and olives (4 to 6 servings) 1 pound spaghetti or vermicelli 5 tablespoons olive oil 2 cloves garlic 1/2 pound imported black olives Parsley Capers, peppers and breadcrumbs (optional)

Heat the oil and add the finely chopped garlic. Before it starts to brown add the coarsely chopped olives and a good handful of chopped parsley. Cook for a few more minutes and then serve with the hot pasta.

Variations can be made by: Adding a tablespoon of capers with the olives; grinding fresh pepper into the sauce or adding some breadcrumbs browned in a little olive oil to the finished sauce. VERMICELLI WITH CLAMS (4 to 6 servings) 1 pound vermicelli 5 tablespoons olive oil 2 cloves garlic Salt and pepper 2 pounds small clams or 8 ounces cooked small clams Parsley

Clams in their shells should be shrubbed to remove sand and placed in a pan over high heat and cooked without any extra liquid until they open. Remove from the shells, strain the liquid through a fine cloth, return to the pan and boil for a couple of minutes. Cook the pasta, drain well and serve with about 6 tablespoons of the clam liquid, a little oil, some finely chopped garlic and parsley, pepper and the clams. -- From "Pasta" by Vincenzo Buonassisi PAPPA AL PMODORO (Bread Soup) (4 servings) 3 large cloves garlic 1/2 cup olive oil Pinch of dried hot pepper flakes 1 pound very ripe tomatoes, fresh or canned 1 pound unsliced white or whole-wheat bread, 3 days old* 3 cups hot chicken or meat broth Salt and freshly ground black pepper 4 to 5 leaves fresh basil, or 1/2 teaspoon dried

*Homemade or bakery bread is preferred.

Chop the garlic coarsely, then place in a stockpot, preferably terracotta, along with 1/4 cup of the olive oil and the pepper flakes. Saute very gently for 10 to 12 minutes.

Cut the tomatoes into 3 or 4 pieces, remove the seeds and add them to the pot. Simmer for 15 minutes.

Cut the bread into small pieces and add to the pot, along with the broth, salt, black pepper and whole basil leaves. Stir very well and simmer for 15 minutes longer, then remove from heat, cover and let rest for 1 to 2 hours.

When ready to serve, stir very well and place in individual soup bowls. At the table, sprinkle 1 tablespoon of the remaining olive oil on each serving and grind some fresh black pepper into each bowl.

Note: Though considered a soup, the consistency of pappa is not liquid at all. It may be eaten lukewarm or cold, or reheated and hot the following day. Do not add any grated cheese. -- From "The Fine Art of Italian Cooking" by Giuliano Bugialli VENETIAN BRAISED SCALLOPS (4 servings) 2 pounds scallops 1 large clove garlic, peeled and split 4 tablespoons olive oil 3 ounces butter 1 tablespoon finely chopped parsley 1 1/2 tablespoons tomato sauce Salt and pepper 1/2 cup good dry white wine (more if necessary)

Wash the scallops well, and place them on a slanted surface to drain. Brown the garlic in the olive oil and butter over medium heat, then remove and discard it. Allow the pan to cool a bit. Add the parsley, tomato sauce and scallops to the pan and place over low to medium heat. Sprinkle on a little salt and quite a bit of pepper. Regulate the heat so that the sauce simmers gently. Cook uncovered for 10 minutes, turning the scallops 3 or 4 times.

After 10 minutes, add the wine. Continue cooking uncovered. Turn the scallops occasionally while cooking for another 10 to 15 minutes. At the end of cooking most of the wine should have boiled away, leaving a rather thick sauce. There should be enough liquid, though, to prevent the tomato sauce from burning. Add more wine or water if necessary. CALF'S LIVER VENETIAN STYLE (4 servings) 1 pound calf's liver 6 ounces butter 3/4 cup olive oil 2 medium onions, chopped Salt and pepper Flour for dredging

Cut the liver into bite-sized slices, 1/2-inch thick maximum. Place the butter, olive oil and onions in a frying pan over medium heat. Add some salt and pepper. Stir frequently while cooking until the smallest pieces of onion just begin to take on a golden color.

Some cooks dust the liver lightly with flour before adding it to the onions. Add the liver to the onions and brown it, turning constantly. This should take no more than 4 minutes, probably less, depending upon the thickness of the slices. Test a piece after 2 minutes. It should have just barely lost its red color and should be firm but not tough. Do not overcook the liver, for it will quickly become too chewy and lose its flavor.

Serve the liver and onions and a goodly amount of the sauce onto warmed plates. --From "Venetian Cooking" by H. F. Bruning, Jr & Cav. Umberto Bullo RAVIOLI ALLA FIORENTIAN 2 pounds spinach 1 ounce flour 2 ounces butter 8 ounces ricotta 3 egg yolks Salt, pepper and nutmeg 2 ounces grated parmesan

Remove the stalks and wash the spinach. Drain and cook in boiling salted water. When the water reboils, drain the spinach. Run cold water over it, and press very dry with hands to remove all liquid. Chop finely and put in a saucepan with the remaining ingredients. Stir briskly for a minute or two and allow to cool. When cold, roll into small pointed sausages, an inch long, flour them and lower into boiling salted water. Simmer and as they rise remove them from the fire. Pour over melted butter, sprinkle with grated parmesan and serve. --From "Leaves From Our Tuscan Kitchen" by Janet Ross & Michael Waterfield