Long sleeves, long pants, and boots up over the ankle, like Wellingtons or Ropers. Repellants should be put on the cloth not on your skin, if you can avoid it. I react to a great many of them worse than to bug bites; so I seldom spray down. The boots are specifically to protect against deer flies, to keep them off your ankles and lower legs. I will spray down the uppers of my boots in deer fly country though.
Deer fly bites (like horse fly bites) very often swell up to the point that getting a shoe on the affected foot is nearly impossible. The biting bugs are always worst in the swampy areas; so you want the camp to be as open and breezy as possible, since that is very likely where it will be worse for bugs than open water is.
Mosquitos are always worse in low light, early or late in the day. IMO the worst are the little striped queens that come out around dusk, and right after dark. In camp if the cabin has a porch light that is not a bug repellant bulb, ask if you can replace it with one. The fewer you attract to the door the fewer will sneak in to pester you when you are trying to sleep. Some always get in anyway; so we do a daily swat patrol and keep the fly swatter handy for any incidentals we see.
Some will swear by this repellant and some by that, but for me there is nothing that is really fool proof. When the fish are biting though I don't seem to notice any bug problems!
Edit: You will never find me fishing in sandals, shorts or sleeveless.