How to Choose Accessories for a Men’s Look?

Lately, I’ve been paying more attention to men’s accessories — it seems that even a basic T-shirt looks completely different with the right cap or belt. What accessories are must-haves for you? Do you have favorite brands or stores where you find interesting pieces?
For example, I recently ordered some stylish accessories from Maverick.ua — they really have a great selection and top quality. Share your tips: what’s most important to you when choosing accessories, and how do they help you complete your look?