Yes! If you don't have a measuring tape, use a piece of string to measure your sleeve length. Then, use a ruler or metal tape measure to find the length of the string.
You could use regular tape, but it won't work as well as florist's tape. Florist's tape is easier to work with and fits in better with the flower because it's...
You can try using stickers or decals, but they won't last long due to wear-and-tear. If you want something that lasts longer, you'll have to use paint.
No. You need to have double-sided tape to make the tape. If you don't have double-sided tape, you can buy it from craft stores, or any other kinds of stores.