The great thing about Express Pass is that you don'y need too many plans. The only 3 experiences without EP are Velocicoaster, Hagrid's Magical Motorbike Adventure, and Olivander's Wand Shop.
If you want to do Olivander's, then do it early in the morning your first day, ideally during early entry. If you just want a wand and don't care as much about the experience of possibly being chosen by one, you can also just buy them in the main gift shops near the entrances of each parks.
Velocicoaster has had a pretty reasonable wait and also has a single rider line, so you don't need to get in line super early.
Hagrids uses a virtual queue, but is open for standby during early entry. So if you're not getting a wand a Olivander's, then I would suggest going here.
For everything else, you can really just go on any attraction whenever you want. The longest wait you'll have is probably 20 to 30 minutes for the Hogwarts Express, and everything else is 5 to 15.