Walk into a corner in any online level while crouching. Continue crouching once you make it into the corner.
Let go of the crouch after you have been crouching for at least five seconds. Proceed to walk away from the corner.
Press the "A" button to jump. Before jumping, make sure you know where you want to jump to. Look for a ledge far away or any place high above that you can jump onto.
Continue jumping forward to the ledge you want to jump onto. Rapidly tap the "A" button and hold the control stick until the last second before you land just short of the platform or ledge.
Stop pressing the "A" button. You will need to land on a crack before landing just short of your point of destination. You will need to know where those cracks are in the levels beforehand. They are typically easy to find and not too far from high platforms. You will now be able to jump higher into the air than you ever have before.
Know your areas and specific hiding spaces in each online level before trying to perform a super jump. Continue practicing until you get the super jump down every time.