Dressed to distress (Male wear)
I'm going to give you my best tips now on what kind of clothing you can bring to Jamaica as a man to :
a) Feel properly dressed for most occassions.
b) Remain relatively cool.
c) Not have to work horribly hard to remove stains.
d) Not go insane trying to get your clothes to look professionally pressed.
e) Be decently unobtrusive.
I have found that a key element to Obtrusive Harrassment Management And Negativity (OH-MAN) is a combination of your walking style, your posture and what your wearing. There may be some OHMAN possible from your ethnicity, I'm not quite sure of this one yet, still experimenting, but for sure, your clothes speak volumes until you get the walk and talk down. Volunteers who violently disregard this factor are constantly confused by the anti-tourist, let's call it rhetoric, they receive. Imagine however, that you are a local, of say, Key West, Florida, or New Orleans, Louisiana and it's Spring Break or Mardi Gras respectively. Imagine now that thousands of drunk, stupidly dressed people are gawking all over the place. The temptation to openly mock, and in some cases, take advantage of them, is overwhelming. You feel great doing it and it makes you feel really like your much cooler than these loser tourists. Besides, you never behave like a moron when you go visit their podunk village, why do they have to act like such idiots when they come to your super-cool hometown? This is what you face in Jamaica.
The key is, dress like you mean business, not vacation. Your "Beers of Wyoming" t-shirt, flip-flops and palm-tree print shorts DO NOT say "I'm here to do a serious job for two years and to help your communities with professionalism and taste". Especially if you walk around a town or city wearing something like that. Shorts are for dancehall kids, rude boys and tourists. You will not be mistaken for the first two. You can wear shorts around your immediate community when you are completely not in Peace Corps Volunteer mode, but otherwise, don't say I'd never said nothing.
So what flies? Here it is straight (a.k.a. what i've seen work, other things might, but this is zain)
1) Button shirts with a collar. I've found that cotton-synthetic blends work really well. They stay pressed, don't make you sweat profusely and wash out really well. My favorite shirt is a 65/30 Polyester/Cotton blend.
2) Polo shirts, sometimes. Polos are not really big in Jamaica unless they are part of a dress uniform and/or have some emblem embroided on the breast. The Peace Corps Polos work well. Regular polos are okay though.
3) Those Cuban shirts with four pockets and pincuffs. That is old-school fashionable, and old men will give you big ups. It's as good as wearing a shirt and tie.
4) Long-sleeve, not white, dress shirts, with a tie. Having the white collar is cool, so it having the collar the same color as the shirt.
5) Dress slacks. With a solid color shirt, this is the standard for presentable young professional men.
6) Khaki slacks. Also acceptable. This is what I almost exclusively wear.
7) Jeans. Jeans are sometimes acceptable, depending on what you do and where you are. Jeans should not be worn with a t-shirt.
8) Cargo Pants are sometimes acceptable also, although I'd not wear them to anything requiring the 'look'. They fly if your going to do some labour/engineering/computer lab work.
9) Black/Brown leather shoes. This is part of the male professional standard.
10) Brown work boots. This has recently become an acceptable young male dress standard.
12) Canvas shoes/sneakers. Are acceptable for labour/engineering/computer lab repair work.
Hats are another issue. Normally, it is acceptable for men to wear a baseball cap. This seems to be relatively acceptable dress wear, as odd as that may sound. Don't bother with other types of headwear though. Straw hats, visors, cowboy hats, fedoras, etc. are either for farmers (which nobody will believe you are) or dancehall fashionistas (which few will believe and/or care if you are). Notice the absence of T-Shirts in my list. DO bring t-shirts. You will want to sleep. And you will have days when your only hanging out, in which case a t-shirt is fine.
Help us to reduce the OHMAN factor. Bring down Babylon by fighting the image of foreigners as only coming to Jamaica as morons. Only you can prevent tourist fires.