First of all, get to the parks early. My next suggestion is to spend the early non crowded period riding non-FP rides and collecting FPs for later. Not everyone knows this, but you don't HAVE to use your FPs during the one hour time they give you. As long as its AFTER the first hour, you can use your FP any time after that, and you can collect a new FP anytime after the first hour too.
I will give you as an example what I did when I was in California Adventure last fall. I arrived at opening and went straight to Soarin and got a FP for 10:20-11:20. Then I went and rode the Sun Wheel. By the time I was done with the Sun Wheel, it was 10:25, my FP time for Soarin, so I dropped by Mulholland Madness and picked up another FP with a time of 10:35-11:35. I rode some other rides in the Paradise Pier section until about 10:40 when I went to Grizzly River Rapids and picked up a FP for 10:55-11:55. I then got in the regular line for GRR because it was only a five minute wait. After that, I went to Soarin and used my FP, picking up another FP for Soarin before doing so with a return time of 11:35-12:35. I kept doing this-riding non-FP rides and picking up new FPs as time permitted. THEN, in the afternoon when the crowds were bad, I used all those FPs I'd spent all morning collecting.
Most people go directly to Space or Splash Mountain early in the morning which is great, but fail to realize that later when the non-FP attractions are busy they will have no choice but to wait in their long lines. Go on non-FP rides early in the morning and then spend all afternoon going on FP attractions.
I hope this makes sense. I was able to ride Soarin 6 times in one day, GRR two times, and MM 3 times doing this, never waiting more than 10 minutes each time, plus all the other non-FP rides I wanted to.