My "best" tip ...
take the time to
stop and smell the roses.
This is suppose to be a vacation. I see families frantically dragging their kids around the parks with looks of misery on their faces. When they get home, they need another vacation from the experience and talk poorly about WDW because they didn't take the time to truly enjoy it. It's not going anywhere! It still surprises me how neurotic and honestly pushy people get at WDW (usually newbies).
We
ALWAYS make sure to plan a "resort day" (usually when we plan to attend an Evening EMH). You've paid all this money for this wonderful resort, take advantage of it's amenities. We wake-up late, swim in the pool and maybe even venture to other resorts to check-out the ground and restaurants.
Don't burn the candle at both ends by trying to stay up late at a park and then getting to rope drop the next morning. You can physically make yourself sick. No one wants to be sick at WDW.
Have a magical trip y'all!

Jennifer