Shido Boss

So far I have been grinding in Mementos while working on Confidants so I was wondering what I should work on to get prepared for Shido Palace Things like Skills I should learn for my party members Personas I should fuse/make Skills I should input on them Maybe items but I probably have that covered I do realize that I'm at the right level for the Palace although I was a bit over leveled due to beating the Reaper although it took a while I was at Level 56 and one or two levels less for my party members Anyway that's all I wanted to know Any assistance is welcomed