Tuck your pants leg into your socks so the black flys do not crawl up your legs and put a rubber band around your shirt sleeve. Put a bandana around your neck to prevent them from crawling down your shirt. The less skin exposed the better off you are. Bug netting is also a good defense if you plan on spending long periods of time in wooded, wet areas. These insects also go after exposed skin.
Insect repellents work well.
Be sure to follow the products directions carefully. And remember, a small amount goes a long way. Also be sure to have a tent that has proper netting and all the zippers work. Let us know what we should add to this section.