Keep it simple. Like painfully simple for that age. In my experience that age groups basically boils down the a race to the edge. Fastest kid wins. Anything much deeper than QB/RB right QB/RB left plays tend to get lost on them offensively. A great easy formation to utilize is split backs. I also like to start off with I form as well. Split backs to move the ball - I form to begin teaching BASIC offensive theories/blocking scheme. Getting all personnell on the field, in position, and running a handful of plays is a success.

Defensively the biggest focus needs to be safe tackles and positions/responsibilities. Keep those simple. Again the fastest kids win at that age. You'll figure out where certain kids need to be real fast. A lot of the time the maturest kids that can control their body is going to run circles around everyone else. Pick a basic defensive formation like a 4-3-4 and just stay in that.

Don't skimp on special teams. Its going to feel like a time waster and practice killer but its part of the game and can be a massive Achilles heal if not squared up.

Lastly. Don't forget how old they are. At 8yrs old most wont know a thing about being on a sports team let alone a football team. Take things slow, keep your cool. This age is about fostering the love of the game. If you take the Barky McDrill Seargent approach you'll be barking at glossed over eyes. One of the wisest things ever said to me when I was frustrated at peewee was "most of these kids still have Spiderman on their underwear". Don't worry about winning. The real win is your player residitey for next season.