I expect many new players don't know this, though I could be wrong.
Spells from equipped items and pets are optional when building your spell deck. Usually when you equip armor, wands, and pets; any spell cards given by those items are added to your spell deck automatically. When building your deck you can see these equipment spells as thumbnails below the list of regular spells you could include in your spell deck.
You can click one of these thumbnails to place a large red X on it. This will make sure that it won't appear in your deck during battle.
For example: I have an amulet that adds two myth shield cards to my deck, the amulet also gives me a lot of health. I need the health, so I want to wear the amulet. I do not always need those myth shield cards, so I can edit my deck and place an X on both of those thumbnails. Now I won't draw those myth shields during battle and I still get to have the health that the amulet gives me.
