<p>Depends on your body-fat percent; i.e. if you’re of above-average muscularity go for well-fitting (but NOT tight!) T-shirts. If you’re overweight, don’t wear t-shirts. If you’re in the normal range, look for A&F, Lacoste etc. for quality if you can afford it.</p>
<p>For layering, to be honest most people I know layer because otherwise they would sweat right through their shirts and that just looks disgusting. plain white T under most shirts looks good, not all though. You should be layering if you’re going to be wearing pullovers in my opinion. There are some really fancy combinations that I’ve seen like shirts over hoodies etc, but that’s not for your average person.. I’d say stick with Ts under polos & shirts, and double-Ts or double polos occasionally.</p>
<p>EDIT: Boss for plain white Ts.</p>