Hey fellow Planeswalkers! When it comes to deck-building in Magic: The Gathering Arena, always remember to have a good balance of cards in your deck. Include a mix of creatures, spells, and other card types to ensure versatility in different game situations. Don’t forget to pay attention to your mana curve too – having a good spread of low to high-cost cards will help you play more consistently throughout the game. And most importantly, always playtest your deck to see how it performs and make adjustments accordingly. Happy deck-building!