For this step first, you must first make a rough sleeve and then improve it.
1) Fold the cardboard around the cup and use the pencil track a line around the cup closest to the top and bottom
2) Cut the carton according to the lines.
3) Using tape, place the cardboard around the cup.
4) To define the top line, place the cup up and down on a flat surface and place the pen over a fixed object at the desired height. Press the pen point on the carton and rotate the cup until the line meets.
5) To define the bottom line Repeat step 4 but with the cup upright.
6) With the scissors cut a straight line from up to the bottom of the template.
7) admire you pattern; -)