Basically, here are the strategies I've found that work well.
1) Avoid the early entry park that day, or if you do go, do rides the first hour and then leave.
2) Get to parks at opening. Stay until lunch. Eat at a resort and then go to a pool/water park. Return around dinner and stay until closing.
3) First thing, get Fast Pass for rides you like and then ride the next closet ride. This works great with ToT/RnRC in MGM and MS/TT in Epcot. Note Fast Passes often run out before afternoon on busy days.
4) Early in the trip, try to pass up rides with large lines. They usually thin out (either first thing or last thing).
5) If you pass Peter Pan and it has no or little line, ride it.
6) Always scope out the lines before committing. I've seen the Test Track line for Fast Passes stretch deep into Epcot while hte standby line was manageable and the single rider line was non-existant.
7) Near closing, lines can look longer as they cut outt switchbacks. This exaggerates the line and lets them minimize the people in the ride.