Your opening hand, or 'mulligan,' is incredibly important. Generally, you want to keep cards that allow you to play on curve (play a 1-cost on turn 1, 2-cost on turn 2, etc.) and have a clear game plan. Against aggressive decks, look for early blockers and removal. Against control, seek out your win conditions or card draw. Always consider your opponent's region(s) when deciding what to keep. Don't be afraid to throw back your entire hand if it doesn't fit your strategy or the matchup. A good mulligan sets the tone for the game.
