You won't have any trouble at all finding someone who can tell you how to fit in.
They can tell you what to wear to that restaurant or this conference or that funeral. It's not that difficult to figure out how to fit in. If fitting in is your goal, you should be sure to get great advice on how to do that.
Standing out, of course, is trickier. Stand out too much and you're a jerk or a fool.
Clothing is not the point. You have this choice to make in everything you do, from your career to the words you use in a sales letter.
The point: choose.
Are you doing this to fit in or stand out?