The bottom line: Women on the make should adorn themselves in red, but for the company party, consider a cool blue instead.

Get there before the food is served (or attend stingily catered parties).

Ravenous men prefer a slightly heavier woman than do men who have recently eaten. (Women don't display such preferences.)

In two studies, researchers staked out the doors to college cafeterias and queried students about weights and shapes of their ideal mates. Men who were waylaid prior to dinner chose pictures of heavier, relatively thick-waisted women more than did men who were interviewed full of food.

The difference in weight preference wasn't huge: about 4 pounds, according to one study. "A hungry guest may have a very slight preference for a heavier body mass," says Martin Tovee, a professor of visual cognition at Newcastle University and coauthor of one of the studies. "But I think you have to get your guests pretty hungry."

Why it might work: In times of famine, fat is good. And if you're feeling hungry yourself, food might be scarce in your neighborhood -- so you want to make sure the mother of your children has the padding she needs to survive. (Men can get by with far less body fat, so a woman's preferences should depend less on whether she managed to grab a few mini-quiches from the buffet.)

The bottom line: A guy's growling stomach might tip the scales in your favor -- but don't count on meager finger food alone to camouflage saddlebag thighs.

Men, surround yourself with women. Women, surround yourself with women too.

In a study, college women rated men who were photographed sitting in a courtyard with female companions as the most attractive, desirable and suitable for romantic congress. Less desirable were men sitting with groups of men; solitary men were at the bottom of the hunkiness pile.

Male participants found women equally enticing whether they were alone or with other women. But women in a group of men dropped dramatically in attractiveness.

Why it might work: Simply looking at a man won't reveal if he's got what it takes, evolutionarily speaking -- the ability to provide for a mate and kids. So a smart woman looks to a man's buddies for clues, says Sarah Hill, professor of psychology at Texas Christian University and coauthor of the study. If he's surrounded by other women, that means other women have sized him up and like what they've found.

For men, however, if a woman is surrounded by men, chances are good that she's already spoken for -- and probably not worth the effort.

The bottom line: Whichever gender you are, bring along a wing woman.

Mingle with the down and out if you're carrying a few extra pounds.

Men who feel poor prefer plumper women -- about four pounds' worth, according to a 2005 study in which 257 college men and women were manipulated to feel poverty-stricken through a depressing financial survey while others were made to feel flush. The have-nots reported preferring a heavier ideal mate than the fat-cat group. (Women didn't change their preference.)

All it takes is the feeling of relative deprivation -- not actually living a life of ramen noodles and no cable TV, says Leif Nelson, a professor of marketing at UC San Diego. The observation may be especially useful to opportunistic females this year, with the economy in the toilet.

Why it might work: "In wealthy cultures, thin women are idealized, whereas in poorer cultures, a heavier form is idealized," Nelson says. When economic times are tough, men can't afford to choose a skinny wife who's at risk for malnutrition. (Not that men are worrying about malnutrition when they check their 401(k) plan for the umpteenth time: It's all unconscious.)

The bottom line: Recessions might as well be good for something. Rubenesque women: Feel encouraged to crash parties on Wall Street.

Don't shave your face the day before.

That's the advice from a study published in June in the journal Personality and Individual Differences, in which women were asked to evaluate five stages of beard growth on computer-generated male faces. A man with a light stubble was the most attractive. A man who cultivates a light beard will look especially dominant to a woman. One preferring to follow Al Gore's lead and grow a grizzly on vacation will be perceived as more masculine, aggressive and socially mature -- and older-looking. Smooth-skinned, baby-faced men appear, not surprisingly, young and unaggressive, and the least attractive.