100% deet comes in sprays and wipes and is the most effective. It will destroy plastic so you have to be careful. We are usually fine with the 40% deet (also in sprays and wipes). We keep coils burning on patio most of the time - seems to help a lot. Be vigilant - those big, day-time mosquitos carry some pretty nasty viruses.

Deet works well with the sand fleas too - I hear long socks work too, but I can't bring myself to even bring socks to Jamaica.