For Seaworld.
I agree with the All Day Dining and Quick Queue. With QQ, I was able to ride Manta 7 times in 1 day (D'Sis and I had a bet, I lost. I was supposed to ride 10 but fell short on time. Should've skipped Kraken and Atlantis.)
Seafire Inn and Voyager's Smokehouse were our favorite places to eat. Seaport Pizza and The Spice Mill we found to be great to pop in for quick drinks and snacks.
Before going on your trip, look at the hours and park info for your particular day. SW will usually post the hours about a month in advance. Make a plan around the shows you want to see and the times. The 3 major shows are One Ocean, Blue Horizons, Clyde and Seamore Take Pirate Island. As Gina said, you'll want to be at each show at least 30 minutes early to get a good seat. The soak zone seats are the best.

They really get you close to the action.
Make sure to get to the park before opening if possible. You can purchase the All Day Dining and Quick Queue tickets before the park officially opens. Plus you'll get more done before the crowds really start rolling in.
Universal Studios.
There are 2 parks: Universal Studios and Islands of Adventure. Rope drop is a must here as well. Again, you will get more done.
Not sure if you're doing one park or both parks. If you're going to IoA and Harry Potter, hit this area first thing. They are currently expanding the area and I don't know exactly when the new area is expected to open. I know it is sometime this summer.
Get Butter Beer from Hogsmeade if the lines at the carts are long. Less wait in Hogs. If you like beer (adult style beer that is) Hogshead Beer is really good.
Universal sells Express Pass. This pass allows you to skip the lines at least once at most attractions (currently cannot skip Forbidden Journey). You can buy the passes day of. I would wait until then to see if it is really needed. If you're staying onsite at one of the 3 Universal Hotels (Hard Rock Hotel, Portofino Bay or Royal Pacific) you get this perk automatically.
Universal also sells park tickets with this perk as well. Unlimited express pass access to most rides in both parks for each day on your ticket. Tickets are a little more expensive, but might be something to look in to.
Mythos for lunch. 3 Broomsticks is also good. Both at IoA.
I don't have many tips for the Universal side. There were many changes going on when we there in Dec 2012. Since then, new things have come along. I don't know what it's like to tour on that side now. I've read Transformers can get busy. Hopefully someone can give you better tips here for the Universal side (Damo, Macraven, or Metro West).
We also like to go to Universal City Walk for dinner. Usually don't have problems getting a table. Reservations are rarely needed.