Hey fellow Planeswalkers! When building a deck in Magic: The Gathering Arena, always start with a clear game plan. Decide if you want to go aggro, control, or combo. Make sure to have a good mana curve to ensure you can play spells each turn. Don’t forget to include removal spells and card draw to maintain board presence and card advantage. And most importantly, playtest your deck to fine-tune it for the best performance. Happy brewing!