I kind of want to start doing PVP. I don't know what school to use, or what gear to use. I have an Ice wizard level 72, and I heard Ice was really good for PVP so is there anything I can do with that?
I would wait until you've reached the max level on your Ice Wizard.
After that, you'll want to plan out which stats you'd like him/her to have, and pick up treasure cards such as Ice Bird which are extremely valuable assets in PvP to Ice Wizards.
If you haven't already, you'll also want to start working on a pet with as good of stats as you're willing to work for.