Well I'm no pro (: But, uh, my style can't be that bad.
I prefer more loose t-shirts, idky but it looks more proper than tight ones and looks better with anything you throw on.
Also, I really like to wear neutral colors (Oh and neutral colors NEVER go wrong together!), but adding at least a little color to it, but not too much, just like maybe add a ring with a bright color and/or a skinny belt that's bright, earrings, bracelets, etc.
Sometimes if you're matching too much... it just looks ugly, so don't overdue it. For example, it realllly annoys me when I see people wearing a bright pink chunky bracelet, with bright pink bead necklaces, bright pink shoes, and like a funky graphic tee.
OH, I love patterns, except you may have to be careful when wearing more than one pattern at a time, it might look a little too gaudy.
Uhhh I feel like I typed too much? But ALWAYS remember to add some YOU in the outfit (;