In order to maximize time, get FPs for the big rides later in the day. When people flock to the big rides, you go to the others. While people flock to 7DMT, Space Mtn, go the other routes. Don't go on the long rides early, save those for later. If you can hit PP right at opening, do it. Then do the rest of FL except 7DMT (FP it for later).
This is how we usually tackle MK, other parks are similar. We decide on which side of the park we are going to do: Left or Right.
MK (Right): FP 7DMT, Space Mtn, and Splash Mtn
If we are near the front, hit PP, then Pooh, Ariel's grotto, Goofy Barnstormer (usually 2-3x), Dumbo, Teacups, Buzz, and then use Space Mtn FP. If done right, this can be done in 1.5 hours. Check wait times at PotC and Splash. If they are not insane, head over to that side of the park. Do BTMRR. Now, it is time for the LONG rides. These are the rides that soak up time. Use FP for Splash Mtn, wait for PotC, and then HM. Hit IASW, Philharmagic, Carousel, and FP for 7DMT. With all of that done, it is about 1PM. 90% of the rides have been completed.
Yes, it is kind of commando style, but it serves a purpose. I am not in 1-2 hour lines (nothing at WDW is worth that much of a wait), most everything we want to do is complete, and we can either stay for other things or head back to the resort to enjoy the pool and activities.