1. When choosing a pumpkin, look for ones that are very fresh and firm. Avoid pumpkins that are bruised or that have cuts. Pumpkins should have a flat base so they will sit up straight. Make sure the pumpkin you choose is large enough for the design you want to carve. The smoother the skin is on a pumpkin the easier it is to draw on and carve.

2. If you purchase your pumpkin early, you can store it in a cool dry place until you are ready to display or carve.

3. When cutting the top of the pumpkin, angle the point of your knife toward the stem. This gives the lid a place to sit and will prevent it from falling through the hole.

4. Using a large flat paddle scoop is the fastest way to clean the inside of the pumpkin.

5. When using templates or stencils, tape the stencil to the pumpkin and use a piercing tool to trace around the design. This will leave little perforated dots on the pumpkin and carving will be super easy.

6. If the cut edges of your jack-o'-lantern are curling, re-hydrate the pumpkin by soaking it in a tub of water overnight. After removing, allow the pumpkin to drain for half an hour and pat dry. Soaking your pumpkin in a solution of one-teaspoon bleach per gallon of water will help inhibit mold growth.

7. Hydrate your pumpkin! While your jack-o'-lantern is on display, periodically mist it with water to help keep it hydrated. Covering a jack-o'-lantern with a damp towel will keep it hydrated when it is not on display. At night, wrap your jack-o'-lanterns in plastic and refrigerate. This will slow the aging process.

8. After carving, coat the cut edges and the inside of the jack-o'-lantern with petroleum jelly. This will help seal in moisture. Vegetable oil can also be used. Spraying hairspray on the inside of your pumpkin will help increase its life span.

9. Sprinkle cinnamon or nutmeg on the underside of the pumpkin top for a nice scent when the candle inside your jack-o'-lantern is lit.

10. Battery operated faux candles are a safe alternative to candles and can be found in a variety of sizes.

Source: http://blogs.diynetwork.com/diy/creative_juice/archives/2008/09/top_10_pumpkin.html