The above advice is dead on.
I drive up and stay in the cheap hotels.
Now, the most important thing is to be at the gate before the park opens at 9am. That means arriving to the parking garage at 8am, so you can walk to the park (15 minutes), get tickets if needed, and be first at the gate (a long line forms). They usually let you in 15 minutes early, where you'll have to stop at the bridge leading to Hulk, but now you're first here. At 9am, you can get 2 walkon rides on Hulk, a walkon ride on Spiderman, a walkon ride on Dr. Doom, then go to the back of the park for walkon rides on Deuling Dragons. Yes, it's rush rush, but that's the way I like it. In the 1st hour, I've hit the major rides at IOA, and this works on any day.
If going to Universal, then you hit MIB first. Here they have a single rider line, which is the best kept secret around. Each row is 3 seats, so they always need single riders. You usually end up behind your partner.
In the afternoon, you take a long lunch, and see some shows.
As the park is about to close, everyone is leaving and you can get some last minute rides.