must watch the night show "Once Upon a Time" if you go to Tokyo Disneyland... you can enter the lottery to see if you can get tickets in guest sitting area. The show projects the image on the castle with music, lighting and fireworks.
Also remember to install the apps for checking queuing time. If for kids, you must get Monster Inc or Winnie the Pooh fastpass as soon as you enter the park, then wait for another 2 hours to take the 2nd one. Winnie is not exactly the same as the one in HK. Avoid going on Sat/Sun.