well, what I do is I draw what I want, not too detailed though because the pumpkin will fall apartXD then, I tape it to the pumpkin where I want it and take a pushpin and poke holes at a low interval all around the outline of the drawing, then untape the paper and you will have a series of holes in your pumpkin. then looking at the drawing you should be able to carve it or make that cool glow effect...... it wont work if your drawing is too detailed though. Hope it helps!!