Maximum Lives and Magic
You can max out your lives in the water stage. First fight your way to the second stage to the point where there are platforms that go up. Once you get there you have to jump up the platforms to the top and you'll get a 1-up. Next, fight through the level until you get to the point where you're right before the magic book. Take the magic book and keep moving to the right until you see a treasure chest. Go into the chest and you'll come out just past the platforms. Go to the left and jump back up the platforms. Do this trick as many times as you would like!