Step 1: Draw the bottle using markers according to the shape that you want.
Step 2: Cut with cutter. Please be extra careful when you cut. I'm used to using cutter so I can do it fast.If you're not used to using cutter, please do it slowly.
Step 3: One became 2. Draw another "hole" mark with your marker.
Step 4: cut the hole. (please becareful!)
And the end result.