This weekend's attempt was made with a pre-made frozen pie shell, six eggs (I find that a good ratio for a 12" pie dish), about 1/4 cup milk and your chopped up ingredients. You can up the ante by making your pie shell from scratch. Leave out the pie shell altogether and you'll reduce calories plus get to call your quiche a frittata.
If the ingredients are soft (like cheese, deli meat, tomato) you can add them right into the egg mixture. If they're harder (like leeks, onion, broccoli) you should cook them, and let them cool, before adding to the mixture. Pour the mixture into the pie shell and bake about 20 minutes until the egg is cooked in the middle and the top of the quiche is golden brown.