1. Use good pumpkin puree. If the pumpkin itself is flavorless, then your pie will be flavorless.
2. Use honey instead of sugar. Mostly because I love the flavor honey adds and it's (in my opinion) better for you than regular sugar.
3. Sample the batter. I know that's a "no no" in most houses, but I'm a huge fan of tasting along the way. How else will you know if it's good enough to eat or not? In this case, the amount of sugar, cream, and spices completely depends on the flavor of your pumpkin. So it's a gamble if you don't sample the batter.
4. Use heavy cream, not skim milk. The heavy cream adds a little fat, but a ton of flavor. It's not going to taste as good with just milk. Plus, if you eliminate all the fat then you can't count it as a dessert anymore because it will be too healthy so just go for it.