Sea World is a pretty spread out park and there are a lot of shows, so it isn't going to be easy to cover all of it in one day. With the shows I find it is a good idea to arrive at the different stadiums at least 30 minutes brfore the show so you can make sure you get a good seat ( particularly if you're going in the summer so you can get a spot in the shade). There are various "preshow" things going on for the 10-15 minutes before each show anyway to keep you amused and it's a good time to grab a drink,icecream and a rest. With the non show exibits it does depend on your attitude to the experience. If you just want to "tick that attraction off the list" you can be through the following attractions in 2-3 minutes. These are Manatees, terrors of the deep (sharks), Wild Arctic, Penguins, Pacific Point Preserve and the Key West Area (dolphin pool, turtles and stingrays). Alternatively if you want to stay and watch the animals, feed them, ask questions of the CMs and take time to learn something about them then, IMHO you need to be looking at 20-30 minutes at each of these.
If you look at at least 3 hours to see those exibits, 3 hours for the shows, 30 minutes to get through the simulator at Wild Arctic, the same for Kracken and JTA thrill rides, an hour for lunch, a few drinks stops, another hour for the small little exibits they have dotted around, an hour in the kids playground area (if you have them). 10 hours should see you alright LOL. You could of course use your second day free and finish off the things you don't see on your first day. With the show timings it isn't easy to make it to every show without having to plan it pretty tightly ( or run like hell at times LOL) If you have time in your schedule to fit in an extra half day to take in one or two of the shows it will make your visits a lot more leisurely.
Oh and I nearly forgot, allow at least half an hour to receive some hospitality ( free

) from Anhauser Busch. You're allowed a couple of glasses of their products , if your over 21

.