I've visited DisneyWorld more times than I can count...first visit was ON THE DAY IT OPENED IN 1971! I must have been/am crazy. Whatever.
Since you're staying on the property, suggest you take advantage of the early admission (1 hour before the parks open to the public) and head first to those attraction/rides that are your highest priority. Saves lots of time.
Also, since you'll be close by, you might plan to go back to your hotel around noon for lunch, (much cheaper than on the property) swim, nap, whatever, then go back to the park rejuvenated for the rest of the day.
And, when you enter the park(s) DON'T follow the crowds who will generally head to the right -- instead, start out at the left and circle the park counter to the majority of the visitors. The stuff on the left tends to be less visited earlier in the day, while the attractions on the right side tend to be crowded.
Souvenirs are EXPENSIVE -- and at the end of each ride/attraction, you'll be herded through a "theme" gift shop. Set and stick to a budget for this crap these mementos and buy them at the end of the day...otherwise you're stuck carrying it all day (although you can have your purchases held at guest services till you leave.)
Pretend you're a kid...have a great time!