Hey there, fellow Planeswalker! When it comes to deck-building in Magic: The Gathering Arena, it’s all about finding the right balance between your spells, creatures, and mana curve. Make sure to have a clear game plan for your deck – whether you want to control the board, go aggro, or outvalue your opponent. Don’t forget to include a good mix of removal, card draw, and win conditions. And always playtest your deck to see how it performs in different matchups. Happy brewing!