When you are catapulted into the air by a spring, keep pressing B. The longer you stay in the air, the more points you will get. The power meter will also increase. This is easiest to do with Blaze. Get on a spring and then keep pressing B until you are a little bit closer to the spring. Then, press R + Up and keep pressing B until you land. This will also increase your Trick Bonus at the end of the stage.