1- The Wizarding World of Harry Potter
The Wizarding World of Harry Potter is must. Everyone who visits the world, even if they are not a fan of the books, movies, etc., walk away with an appreciation of the World of Harry Potter. To really enjoy everything you should plan more than a few hours, because often the wait for Escape From Gringotts can be several hours during busy times. Also consider doing this part of the park later in the day around 4pm when most others are heading back to their hotels.
2- Universal Hotels: It typically can be more expensive to stay at an official Universal Hotel— but one of the perks of staying at one—- is early park admission. You get to enter the park one hour before the theme park opens to other regular paying guests this even includes Volcano Bay. Visitors find that this extra time is just what is needed so everyone gets to do everything they want to do at the park. Here is the link to the hotels available at Universal: https://www.universalorlando.com/web/en/us/places-to-stay/hotels/at-a-glance/hotels-overview
3- Avoid the crowds: One the best time of year is late September and October because schools are back in session and most adult summer vacations are over. Plus, temperatures are not as hot as the summer but still warm enough to enjoy everything including the water parks. Early December is also good because the parks are decorated for the holiday season and many families are to busy shopping, cooking, wrapping presents to be traveling
4- Citywalk: Citywalk has lots of restaurants to choose from within walking distance of each other, plenty of shopping, movies and live entertainment. It makes it for an easy and fun evening with friends or family.