if you havent already, backup your nand! it's always good to have a backup handy so you can recover from a brick. also download sdcaffine from the hb store if you would like to download some mods for your games, one mod i recommend is 4xM for smash :)

NAND Backup is the best tip. If your Wii U bricks because of some Settings, you can restore your backup. And keep the backup somewhere safe. I keep mine in a Folder on my iCloud + drive.