First up, the most important question of all: How can I avoid becoming a matching dude?
Loyal readers, it really sucks to match another dude, so you want to avoid accidental color coordination at all costs. Obviously, you cannot control what every other dude at a party wears, but you can anticipate common outfits and plan accordingly. Here are some tips.
Be original. Wear things that are uncommon and define you. Expand your repertoire of colors-experiment with some mint green or orangutan orange, for example. Rock shorts in the winter, or stick with ankle socks when mid-calves are blowing up. After you shower and lotion your skin, pick out some clothing, and ask yourself if you've ever seen anyone wearing the same outfit. If you the answer is no, there's a good chance you won't have to see your nice tank top draped over some douchebag doppel-hanger standing across the room.
Avoid name brands. Most clothing is made by major clothing companies, but if you stick to off brands and generics, you have a trump card: when three dudes are wearing the same Patagonia fleece and someone accuses you of being the fourth, you can proudly point to the logo and announce that you purchased your pullover at Walmart.
Learn to sew. If you made it yourself, you can guarantee that nobody else owns the same shirt. For a very reasonable price, you can pick up a Singer or a similar product. Everyone wins: you don't match, other people don't match you, and you get to boycott companies that force 12 year old Cambodians to work 12 hour days in substandard conditions. You're such a good person!
Don't be a hipster. America, and probably other countries, is filled with disillusioned youth who lament the rise of commercialism and conformity. They turn to bizarre fads like goth, scene, emo, politics, and, the most loathed trend, hipster. They don't want to dress like "everyone else," so they seek out flannels, trucker hats, ironic tees, and jeans that drastically lower their sperm counts. Problem: they fail to realize that millions of other kids who got teased on the playground are also shopping at American Apparel and Urban Outfitters. If you're going to advertise your originality, make sure you're original about it.
Cross-dress. If you dress like a girl, you probably won't match any dudes. Of course, you might match a girl, and that would be super embarrassing. On second thought, do not be a transvestite. Yeah, J. Edgar Hoover was still successful, but you don't have the secrets to blackmail 95% of important people in America.