I have been carving pumpkins for years. Each year they get more difficult, more detailed and take longer to complete. But the results are totally worth it.
Step 1: Before You Start to Carve
Exacto Blade or very sharp knife
Pumpkin carving blade
Spoon or pumpkin scoop
First, I never cut a hole in the top of my pumpkins. I cut a hole large enough for my hand (with a pumpkin scoop) to fit through, on the bottom of the pumpkin. then I throw away the bottom I cut out. I use the scoop to clean out all the pumpkin guts and scrape down the side I am going to put the template on.
Step 2: The Template
I have been known to use pre-made templates, or make my own. Because I have pictures of the steps done, I will show this one which is a pre-made template. First, I make a copy, so I have 2 copies of the same thing. One to carve, one to look at. I tape it to the pumpkin (sorry no picture of this) and then I use an exacto knife to go around every line. I do not cut through yet, I just want those lines to be totally on there. Then I pull the template off.
Step 3: Just a Little Flour...
The secret to being able to see what I previously carved is using flour over the cuts, just as soon as you pull off the template. The pumpkin oozes a bit of moisture, and the flour then sticks to that. Its not particularly easy to see, but a tablespoon of flour rubbed all over the cut pumpkin makes life easier.
Step 4: Carving
I absolutely use the little pumpkin carving saws that come with the kits. They are, by far, the best way to carve all the way through the pumpkin. I start in the relative center of the design, and work on the smallest cut-throughs first. Then I move on to the larger ones, moving up in size. When I am done carving through, I take that exacto knife I used earlier, to clean up the edges. I also do my best to bevel the inside cuts even deeper, leaving the skin at the outside edge, and taking off as much as possible angled in. This allows for the maximum amount of light to be let through.
Step 5: Shaving It Off
Sometimes when I use my own stencils, or even pre-made ones, they require just shaving off the skin. I posted some older examples of shaved pumpkins (you might guess that year's theme)
Step 6: Testing, Testing
I generally use tap lights inside my pumpkins, to get the best glow. Sometimes I use other lights when I am looking for a particular effect. I use the tap lights because they tend to be bright enough to tell me if I need to thin out the pumpkin wall more.
Step 7: Done
I have posted many pictures of the pumpkins I have carved. We tend to have a theme for the year, whether it is wild animals, Spongebob, Mario, Suicide Squad, or this year's theme, The Nightmare before Christmas. I like to have 5-6 pumpkins for the year. My daughter has been improving yearly, and she actually did the Deadshot and Kitana last year.
Hope this was helpful in understanding how to carve an impressive pumpkin.