Hey fellow Planeswalkers! When it comes to deck-building in Magic: The Gathering Arena, always start with a clear strategy in mind. Focus on a specific win condition and choose cards that support that goal. Remember to balance your deck with a good mix of creatures, spells, and other cards to handle different situations. Don’t forget to include some removal and card draw spells to maintain control and keep your hand full. And most importantly, playtest your deck regularly to fine-tune it for maximum efficiency. Good luck, and may your opening hand always be full of land!