Most Helpful Guy
Get measured, know different styles and materials. XL, L, M, S. Loose fit, Boot cut, Tapered, Slim fit, Fitted. Cotton, Polyester, Fleece, Spandex, Rayon. Find your colors and balance them. Don't wear white pants with a black shirt, because it never works. Don't wear a white shirt with black pants, if you're pasty white. Don't wear all black, unless your clothes fit your body and you have a bit of silver and/or burgundy. Try clothes on, try (neatly) folding/rolling your sleeves on certain shirts. Workout so you can fill in your clothes so that you fit your clothes rather than your clothes trying to fit you all the time, meet them half way.
Cut your nails after every 3rd or 4th or so shower. Get pomade to style your hair. Speaking of which, try out different hairstyles. Try long, short, fades, tapers, reverse tapers, choppy, and so on. Facial hair? How do you want it? Stubble? Beard? Goatee? Don't do shitty designs, you'll look like a filthy casual.
Take care of yourself. Wash your face with a mild exfoliant (salicylic acid 1% at least or get something natural or just water/soap if your skin can take it), drink water, eat fruits and vegetables daily, cut out dairy if you have acne (see if it helps), and sleep at least 7 hours a night.