Hey fellow Planeswalkers! When it comes to deck-building in Magic: The Gathering Arena, one important tip is to maintain a good balance between spells, creatures, and lands. Make sure your deck has a consistent mana curve to ensure you can play your spells when you need them. Also, don’t forget to include cards that can deal with different types of threats to increase your chances of victory. And lastly, always playtest your deck to see how it performs and make adjustments accordingly. Happy brewing!