Image building

In order to be percieved as worthwhile to a girl, you MUST know how to dress. Dress is important because it is an external portrait of who you are inside. Girls size a man up at a glance by looking at his outfit. "Well I dress fine" you say. Well that is your pride and your internal comfort net speaking. You may however be an amazing dresser but that's only if you get compliments everywhere you go, like myself.
Truth is guys arent great dressers, typically, because we are told by society that a "shopping man" is queer. Our clothes are bought for us by older females in the family who take us in to the dressing room as a young child, give us a pair of wranglers then turn us around and give us the one finger pant jiggle to make sure that the clothes fit right. They give us the older clothes of our brothers which are generally 2 sizes too large and tell us how handsome we are, or they scout the clearance rack for the first thing that resembles fitting.
FIT is the first thing you want to look for in an article of clothing. You want to buy a pair of pants that compliments, or at least shows you have an ass. Shirts should be snug on the shoulders and should not balloon out or drape to your knees.

Shirts-
Typically I search for a Modern Fit, or look to see if the tag says fitted. A shirt could look awesome but if it doesn't fit right you look try-hard and it ends up being wasted money.
In a club environment I would stay away from plain button-ups or striped polos, just because it is a common high-school, college, gangster look. to compliment a solid or striped button up I prefer to wear another fitted t-shirt over it. Graphic tees preferrably. Make it a point to stay away from shirts with sarcastic remarks on them.
I also stay away from band tee's as they never fit right and ppl will judge you based on the band you are wearing.
I tend to stay away from mainstream stores which leads me to small shops where i WILL pay more in. Jumping up an extra 30-40 dollars for a unique shirt is well worth it to me if i know that I will not run into another guy wearing the same one.

pants/ jeans-

Pants are the foundation for your wardrobe. A pair of pants can make or break you. I prefer to find the closest fitting jeans I can find. diesels, tru religions, sevens and more are the higher costing jeans but they look so fucking good that they are worth it and generally turn heads. I've also found great jeans at hollister or Buckle. Guess also carries great jeans. You can also wear slacks which is a look I go for in the summer. The idea is to find pants that are not too long and wont be stepped on while at the same time preventing the crotch from hanging to your knees. Purchase pants that make your legs look more full and muscular. I stay away from the skinny ankle jeans as it's a grungy emo look and because boot-cut jeans cover your shoe laces which is an ocd trigger for me.

Shoes:

They say a woman can read a man through his shoes. I stick with Brown dress shoes, or comfy slip-ons that are unique. For instance in the summer I go for the look of a rockstar so i will wear some ed hardy converse or some stylish pumas. I generally like to stay away from tennis shoes because they dont work well with my style.

belts-

Belts must match a mans shoes. That is the only firm fashion rule I have heard for men besides dressing in seasonal colors. I veer away from solid colored belts as they bore me and find belts with riveted loopholes instead. Always have a belt buckle worth looking at, but try not to come off as a member of a boy band unless that image is congruent with who you are.

Socks:
should match your outfit, but I rarely wear them.

Accessories:
Arm bands-should match belt in color
Necklaces- should also match belt, and armband. if they are metal then the color should reflect elsewhere also.try matching it with the metal of your buckle.
rings: look around for rings that are completely unique and don't overdo the amount you wear at a tim i try to stay at 2-3 rings per hand maximum.

These are basic guidelines that I see most established dressers follow. Dont be afraid to try something different but be open to suggestions and opinions. Most dress styles are subject to congruence and personal preferences. I get asked if I am gay a lot but I am completely comfortable with my dress and recieve way more compliments than negative remarks