Jump a lot to maneuver around them, and attack only when you know they can be punished, don't be too hasty.
Against a lot of projectiles, Wizard's foot will eat through them and hit your opponent as well, but in order for you not to clank with their projecitle, you have to wizard's foot a bit ahead of time. If you wizard's foot when the projectile is too close to you your wizard's foot will cancel it out instead of going through it. I think this is because wizard's foot is slightly weaker at the beginning, so it's not strong enough to go through it. Remember that the Belmonts have a lot of lag when they throw axes so dash attack or wizard foot them while the axe is still in the air.
Shield against the holy water bottle so it doesn't start the fire. Wizard's foot early enough and you'll go through their cross, Link's arrows, and boomerangs. When opponents throw items that you can steal and hold yourself, your opponent might start shielding a lot, and you have flame choke which will allow you to grab them even while holding an item. You can bully the crap out of K. Rool if you steal his crown, don't let him reflect it and don't be reckless and let him get it back.