Also regarding the stereotype, nothing breaks down a stereotype more than a nice smile and being positive. When you pass someone on the street in the morning.....say 'Good morning!'
What about cubavera shirts? They go well with both khakis, shorts and jeans.
A safe bet is a good pair of dark jeans and a good t-shirt (I like a V-neck). When it comes to clothes for a guy and if you have a limited budget, is to buy less so that you can spend on better quality. I think button down shirts in solids are always a good look too with jeans. They also pair up nicely with shorts. For shoes, in the summer, leather sandals, nice flipflops, or athletic shoe. Personally I like my 'Barefoot' Merrells. Merrell has come a long way and are no longer just about hiking. If you are lean, go with a slim fit. And get a nice watch. I know a lot of guys skip out on watches now because they have a cell phone. But a watch is the best accessory a guy can wear.