A few golden rules of fashion from a clothes horse (mostly having to do with "dressy" styles):
1. Pleated pants should be avoided at all costs, as are trousers with pegged legs (tapered from wide in the thigh region to narrow at the break). Flat front, straight legged pants are a timeless, classic, and elegant look.
2. Baggy and boxy button down shirts aren't flattering on ANYONE (this is the way most US designers make their dress shirts). Make sure your dress shirts (or any shirt with buttons) taper down at the waist so that when you tuck them in, there isn't that strange bulge of extra fabric hanging around your belly like a phantom spare tire.
3. Never buy any article of clothing that has a "Dockers" tag attached to it anywhere
4. Never EVER wear a tie with a short-sleeved shirt or cotton pants. If the situation is formal enough as to require a tie, it is formal enough to require wool slacks and a long sleeved shirt as well.
5. Unless you really know what you are doing, stick to basic black dress socks, shoes (without tassels), and belts (avoid brass-colored buckles; stick with silver/pewter).
6. Unless you are going for the "mod" look (i.e., the uber-thin ties), a quality tie should make a reasonbly big knot in a half-Windsor with a dimple in the part of the tie hangs from the knot. The tie should be long enough that the tip comes to the center or bottom of your belt buckle when tied. I'm sorry to be the bearer of bad news, but it's impossible to get a decent tie for under $50 unless you get lucky and find one on sale somewhere. The median price range for a decent tie is about $70, so take care of them. Silk ties start to fall apart if you don't take care of them.
7. The best places to get current fashions at semi-reasonable prices in my experience are Nordstroms, Banana Republic, and Kenneth Cole (although each of these stores has its own unique fashion-disaster traps that you have to learn to avoid). Also, don't pay full price. Wait for the stuff to go on sale, and then stock up.
8. If you are going to stuff a sock down your trousers for the day, avoid knee-high tube socks. Noone will believe you. If you choose to use a cucumber, don't wrap it in aluminum foil if you have to go through airport security (as the bass player from Spinal Tap so aptly demonstrated).
