I see two primary problems. (Perhaps you have identified others; if so, please let me know.)
Problem 1: For casual dressing, we denizens have fallen into the easy, characterless, slipshod uniform of T-shirts, blue jeans, and white tennis shoes. Note to denizens: DO NOT DRESS LIKE THIS. Unless we want to appear boring and slovenly, we must wear other garments, clothing that expresses our individuality.
Problem 2: Many denizens equate “skin-tight” with “attractive,” as witnessed, for example, in the apparent fetish with Spandex and muscle shirts at the gym. Note to denizens: Please forgive my saying so, but such dressing is a bit chav—and that’s not a good thing.
(Related note: Gentlemen, a glimpse of gold chain is acceptable, but please, no full-monty, gold-chain views on a hairy chest. We beseech thee!)
Below are several fashion videos that fashionistas and dandies will enjoy and others can draw inspiration from.
Esquire's Best Dressed British Man
The Iconic Kate Middleton, Duchess of Cambridge