in pieces and putting them on, like you did the first layer. continuing to cut in 5 inch lengths will take quite a bit longer but there will be less crinkles.
check to see if there are any thin spots by squeezing it lightly in different places. add more to thin spots you may have missed. it should now be holding the shape fairly well. if you want it stronger, add more layers of tape. some of the cheaper packing tape seems a bit thicker and will require less layers to hold it's shape.
when you have enough layers, hold the tied piece of the balloon and use the scissors to cut 