I lived deep in the woods in Northern Ontario for most of my childhood. Mosquitoes weren't much of a problem, but every single day we didn't have snow was a battle against black flies. They would wriggle their way between folds of clothing, into hair, and would bite open bleeding holes all over your body. After coming in from outside, they would crawl off us and congregate at all the windows in the house . . . and my mom would use a vaccum cleaner to suck them all up. We used to joke that we needed to keep the dog on a lead so the bugs wouldn't carry her off.
Get a bug spray with the highest percentage DEET you can find and use it regularly. Don't go out at dusk, or in the early hours of the morning. Try not to go out when it's overcast, or not very windy.
Once bitten, the most important thing is to NOT SCRATCH. It will be itchy as heck, but every time you scratch the bite it just extends the itchiness. If you scratch it a lot you'll end up with a big bump and might end up giving yourself lifelong scars (ask my sister . . . who was never able to prevent herself from scratching). Try to stay cool. If the itching gets really unbearable, apply some ice to the area. Calamine lotion helps a bit, benadryl cream helps a bit. Not scratching helps more!