HOW DO you look at art in a museum, anyway? Do you trudge methodically around each room, leaning in at each picture to read the title off the wall, then stepping back, glancing and moving on? (Some scorn to read the title; they just nod wisely and look proprietary.) Do you go only for the show of the moment? Or do you head for the postcard racks and never bother with the paintings at all?

The Phillips Collection at 1600 21st St. NW is a great place to practice museum-going. You step into a high-ceilinged room, find a picture you like, sit down on a sofa and spend some time with it. There is little sense of people rushing past you, making you restless to move along with the tide. It is more like being early for an appointment in someone's elegant house: you sit there and let the walls talk to you.

As nearly everyone knows, the wonderful Renoir "Luncheon of the Boating Party" and 74 other Impressionist masterpieces are on tour until next January, raising money for next summer's massive renovation and for the endowment. Already it has been seen by 360,982 people, almost four times as many as visit the Phillips in a year.

But even if you can't see the Renoir people, with their delicious skin tones and straying glances, or the Monet cliffs in that blinding summer haze smelling of the salt air, many old friends are still hanging around.

There is a roomful of John Marin watercolors, but you don't have to study them all. Concentrate on a couple of seascapes with their deep, cool blues. Feel the power of the hypnotic sea horizon, the suggestion of breezes on the waves. Then check out the others if you feel like it. Or move on. You're not taking a test.

Roaming through the human-scale chambers, you come upon the charming "Interior With Egyptian Curtain," a joyful shout of a picture, exploding with bright colors and sunshine. Many artists have tried to paint with the innocent freedom of a talented child, but no one came closer than Matisse.

In the room that held the big Renoir is another Monet, "The Road to Vetheuil," perhaps not everyone's favorite view of that village but still a lovely study of shadow and light quality in the country when the year is young but the day is getting on.

It is interesting to go from this one straight to Courbet's "Winter in Jura," as dark as the Monet is airy, gloomy with the yellow light that comes just before a snowfall. You can almost smell the moist cold freshness of the air and feel the cold through the shoes of the woman trudging down the country road.

There is a bench in front of Cezanne's "Mont Ste. Victoire," one of many versions he painted of a rather ordinary scene in Provence. Any number of art-minded tourists have photographed the same view Cezanne had. But they can't bring the magic to it, because he painted the idea of a mountain, a mountain modeled by light, a series of rhythmic color changes. After Cezanne, people never saw landscapes quite the same way again.

And after you've been to the Phillips, you never see museums quite the same way, either. Would they were all as quietly inviting. Would they all gave you the feeling you could visit just a dozen, or five, or two paintings and get on with your life, mind and feet refreshed.