A #2 Xacto blade can help you make small, detailed surface cuts, & a #15 blade can help you make detailed deep cuts.
A keyhole saw can help you make larger deep cuts. The flexible blade helps when making curved shapes.
A fleshing tool can help you to thoroughly clean the inside of an organic pumpkin, preventing the pumpkin from deteriorating too quickly.
A linoleum cutter can be used to make detailed cuts in the surface of the pumpkin.
To keep an organic pumpkin from deteriorating prematurely, submerge it after carving in a solution of 1 tablespoon of bleach per gallon of water to kill the bacteria that would cause rotting. Alternative, you can regularly spray the inside & carved area the same mixture.
For candles that require a plug, carving the lid in the bottom of the pumpkin works best.