Rope Drop- My #1 tip for everyone is to get to the parks as soon as they open (when they drop the ropes). I know waking up early on vacation doesn't seem appealing but beating the crowds, heat and riding most rides by noon is a lot more fun! You can always take a mid-day break to relax.
Mid-day Break- Speaking of mid-day breaks, take them! Your sore feet and sleep deprived brain will thank you! Also, it's HOT in Florida so taking a mid-day break from the heat and crowds is a win-win in my book! Go relax by the pool or take a nap in your air conditioned resort room.
Make Fastpass+ Reservations- Why wait in line when you don't have to? Purchase your tickets in advance and at the 60 day mark you will be able to make your Fastpass+ reservations.
Visit Disney During "Value" Season- If you are able, you should visit Disney during the low season. Try to avoid all holidays, summer months, and school vacations and aim for the fall or winter months when school is in session. You will save money on resort & ticket prices and battle less crowds. Of course, with the new Star Wars Land and 50th Anniversary coming to Walt Disney World Resort, the "Value" season could become non-existent. Word of advice - the "lower" crowd season is when school is in session.
Make Dining Reservations- To some it may seem absurd to plan your Disney dining 180 days before you actually arrive but would you rather miss out on the meal altogether? Popular restaurants fill up quickly so make sure you make reservations at the 180 day mark. You will thank me later!
Avoid Crowds at Park Closing - Official park closing is actually the time at which the lines for the rides close but the park doesn’t actually close for at least another hour. Instead of rushing out with the crowds and waiting in long lines for buses and traffic jams, why not spend the extra hour by relaxing in the peacefulness of an empty park at night or wondering through the stores and doing some souvenir shopping. Also, don't miss the Kiss Goodnight on Cinderella Castle!
Avoid Extra Magic Hours - Almost every Walt Disney World Resort guest takes advantage of Extra Magic Hours because they believe it's an added benefit to staying on site. But just imagine almost every resort guest at the same theme park at the same time, that's a lot of people! Although it may sound like a benefit, it's almost always less crowded at the parks that do NOT have Extra Magic Hours. So instead of spending the "extra" magic hours in line waiting for rides, take advantage of the Extra Magic Hours by going to the parks without them!
Media Source: Disney Parks Blog