Here are a dozen tips on contests to guide both your playing and winning.DO . . .

PLAY BY THE RULES. Read the entry blank closely. If the rules say "one entry per person," you risk disqualifying yourself by submitting more than one entry. Most contests reject photocopied entries. Check the rules to be sure. Read the fine print. It often contains important information, such as the value of the prize, restrictions on winning, or the number of stores participating in a drawing.

CARRY A 3x5-INCH PAD WITH YOU. Some local and national contests do accept hand-printed facsimiles in place of official entry forms. (Again, check the rules to be sure.) The usual procedure is to print your name and address on a plain 3x5 piece of paper or card. Games that allow for such home-grown ballots, such as Safeway's recent popular "Football Fanatics" sweeps ("Win a Trip for Two to the Bowl Game of Your Choice") -- ensure you won't be closed out when the supply of official entries is exhausted. Transform down time, moments normally frittered away in lines at banks, check-outs and the daily commute, into balloting for future games.

GUARD AGAINST SALES GIMMICKS. The hook here is usually the offer of a "mountain vacation" or "dream cruise." Other tip-offs: entry boxes and forms that don't specify opening and closing dates for the "drawing" and forms that request such irrelevant, usually personal information as income, occupation, marital status and buying habits.

ENTER CONTESTS WITH SHORT ENTRY PERIODS. Drawings that accept entries for an inconveniently short time can work to your advantage. This is especially true if the rules permit you to enter more than once. One such drawing for a 19-inch color television set was held in each Montgomery Ward store before Christmas to publicize Ward's extended hours. Although contestants in this case were allowed just one trip to the entry box, entries were accepted only between 9 and 11 p.m. on a single night. In addition, entry boxes were confined to the stores' electronics department.

LOOK FOR NEIGHBORHOOD CONTESTS. In contesting, it often pays to think small. Playing games sponsored by radio stations with weak signals, local travel agencies or nearby banks and shops limits the competition and boosts the odds of your winning. Also worth investigating are in-store contests (games confined to a single store) sponsored by mega-businesses, i.e., Coca-Cola, Sears, etc. While these in-store games might not feature the best car, cash or vacation premiums (though even in-stores are featuring bigger pay-offs all the time), these competitions sometimes act as the first round in a big-buck regional or national promotion.

ENTER SECOND-CHANCE DRAWINGS. A second-chance drawing is a sponsor's attempt to award a top prize not claimed during the initial round of play. The pool of contestants during the second-chance phase is usually greatly reduced over the first round.

SUBSCRIBE TO A CONTEST NEWSLETTER. Even the hardiest of contest enthusiasts can't keep up with the constant stream of national contests and sweeps. Contest newsletters do most of the work for you by acting as contest clearinghouses -- indispensable monthly guides to what's playing where and who won what. Often, newsletters also share hints for winning. These strategies can have carry-over value for winning local games. Two of the best contest newsletters are: Contest News-Letter, P.O. Box 4668, Louisville, KY 40204 (a year's subscription costs $14.97); and Sweepstakes Digest, Box 271568, Tampa, FL 33688-9990 ($16.95 per year; editor M. D. Adcock will mail a sample issue of Sweepstakes Digest to anyone who sends a stamped, self-addressed business-size (#10) envelope.) DON'T . . .

ANTICIPATE WINNING. The healthiest contest strategy comes down to this: scope out a ripe game, enter it and forget it. Waiting for the phone to ring or for a registered letter to arrive announcing your big win is the kind of psychic torture most neophyte contesters put themselves through. Veterans have learned it's better to move forward than look back. Get interested in finding a new, even better game, and let the winning take care of itself.

BOTHER WITH GAMES THAT REQUIRE FEES. A bounty of free, no-purchase-necessary local contests and sweeps awaits you. For national games, the only price you should ever pay is a stamp.

FORGET TO SEND FOR WINNERS LIST. A winners list can help put you in touch with individuals in your area who share your enthusiasm for contesting. If a winners list is made available by the sponsor (and publishing such lists is becoming standard operating procedure for both local and national games), take advantage of it. Send a stamped, self-addressed envelope to the address indicated on the entry blank.

BECOME TOTALLY WEAK-KNEED IF YOU WIN. Carolyn Dove didn't. After waiting five patient months for delivery of her grand-prize Renault Alliance from Safeway, the Woodsboro, Maryland woman finally tired of getting the run-around. Moving from empty-handed big winner to consumer activist, she decided to share her frustration with Safeway's president in California. Dove's car arrived 48 hours later.

PUT OFF TAKING YOUR TRIP. Finally, to recipients of vacations and getaways, a tip from the winner of a week in London awarded by a local Maryland radio station: Don't tarry. In this age of takeovers, mergers and corporate tent-folding, your plans for that freebie dream vacation could go up in smoke. It's rare, but occasionally businesses sponsor contests out of sheer desperation -- as an attention-getter or last-ditch effort to generate consumer traffic. If things don't work out, prize winners may be left holding worthless travel vouchers.

Fortunately, the fellow who won London (round-trip airfare and a week's hotel for two) acted promptly, visiting Big Ben within weeks of being notified of his prize. A few months after his return from England, not only was the prize-awarding radio station belly up, but the sponsoring airline was also down the corporate tubes. London, on the other hand, is surviving nicely, and awaits the occasion of your big win.