egkleinmann has a point... on the worst days (high summer for instance, or crazy days like Fourth of July, Christmas, NYE, and others), my advice would be useless. If all the FPs are gone by the time you've burned your 3rd, and you simply can't get 4ths and 5ths... save the FPs for mid to late afternoon.
Almost any other time though... by the time you're ready for the additional FPs, at the very least second tiers like Pirates, Pooh, Jungle Cruise, Haunted Mansion, etc. should have decent availability. You can't count on super-headliners like SDMT (especially) or the 3 Mountains to have availability (though they might, they did for me in April/May), so those are the ones you target with your RD attack and/or your first 3 FPs. My perfect scenario is to hit those top tiers first, knock out the second tiers mentioned at the beginning of this paragraph with the additional FPs, and in between fill in with Tea Cups, Small World and the like, and when all else fails go to Hall of Presidents! TBH, it almost never seems to come to that.
I swear, on my last trip, using this strategy, it was like a flat out magic trick. The only times I ever, EVER dealt with waits was for shows (e.g. Tiki Birds, Philharmagic), where you have to wait for the auditorium ahead of you to finish up and empty... and that doesn't even really qualify as a true "wait".