Step 1: What You Need.
Step 2: Cut
From the remaining part, cut 3 pieces of about 15 cm.
Cut the rest of the tube in small rings shape (as many as you want).
Step 3: The Buckle
Afterwards you can make a knot to fasten it.
Notice the position of the small pieces of the tube and of the rings. There they should be attached to the belt.
Step 4: The Pokets
Run a piece of duct tape through the small tube and fasten it to the belt.
Step 5: The Bottom
Step 6: The Rings
Step 7: The End
You can add some stickers to personalize it.