You will require a template of the shape you desire to cut into your pumpkin, whether that is a half circle, a leaf shape or some other creative idea. Start by folding a piece of paper in half, then sketch 1 side of the shape you desire.
Cut out shape
With the paper still folded, cut the half shape out. This will ensure perfect symmertyfor your template.
Trace shape onto pumpkin
Use a pencil to trace the shape onto the pumpkin. Since you are using regular paper as a template, you will need to hold each little section and trace as you go. Don't worry about little imperfections, the lines will be erased after cutting.
Score & cut lines
Using an XACTO knift or a utility knife, make your cuts by scoring a small area, then cutting deeper after. It may require a couple passes before you are able to get a clean cut that goes through. Take your time, the score-first method is better to maintain fine control of your knife.
Start at smallest point
If you are executing a more complex shape, start at the smallest point and work outward.
Pop out shape
Pop out the shape you have just cut out by inserting the knife and lifting the shape outward. If you try to push inward it may not come loose easily, especially if any cuts were made at an angle.
If you need to, you can go back and shave any imperfections until the shape is exactly what you desire.
Now you can customize each pumpkin or enjoy it in its naturally beautiful state. Use painter's tape and scrap paper to block off the section you don't want painted. Spray paint, and don't be afraid to spray the opening as well; it makes a beautiful colored and metallic glow when you insert the battery powered luminaries. Flickering luminaries have an especially realistic effect.
Use multi-surface paint
Or use multi-surface paint to add a little pizzazz to edges and cover any cutting imperfections. You could also use a metallic colored sharpie to draw designs all around.