Hey fellow Planeswalkers! When it comes to deck-building in Magic: The Gathering Arena, always start with a clear game plan. Identify your win condition and build your deck around it. Make sure to have a good balance between spells, creatures, and lands. Don’t forget to include some removal and card draw to handle any situation. Lastly, playtest your deck to fine-tune it. Remember, a well-thought-out deck is key to victory on the battlefield! Keep brewing those winning decks, my friends!