Hey fellow Planeswalkers! When it comes to deck-building in Magic: The Gathering Arena, always start with a clear game plan. Decide if you want to go aggro, control, or combo, and build your deck around that strategy. Remember to have a good mana curve to ensure you have plays at every stage of the game. Don’t forget to include some removal and card draw to handle any situation. And lastly, playtest your deck to fine-tune it and make sure it performs well in different matchups. Happy brewing!