2. Use unscented personal products (soap, deodorant, shampoo)
3. No bananas! Limit fruit intake.
4. For mosquitoes, apply citronella (mixed with mineral oil), beer, or vanilla extract. For black flies, East Indian hair oil is the best by my experience. Smear it on. In your hair too.
Different things work for different people.
For deer flies, there is nothing to be done except putting a strip of tape on the top of your hat (for them to stick to, like flypaper). No poison works on them.
5. A soap called Skin Armour. Used to be at Home Hardware, now available online in the US. Botannical compounding.
6. Vitamin B patches.
I haven't tried any of the myriad of repellent units on the market, can't stand the coils, so pretty much anything that is a packaged poison is off my radar. No brand names. That being said, St. Francis Herb Farm (Combermere) used to have great natural oils bug dopes, but they disappeared about 10 years ago.
A smudgy fire may also be useful, depending on current conditions and your activities.
Bugs bite more right before a rainstorm, when the pressure changes.