How to make pizza crust thin and elastic at the same time?
I generally use a fairly wet dough and add oil as well. One of the keys is to keep kneading to a bare minimum. This makes for a lighter dough because it has more air bubbles - kneading kills them. As for flour type, I like '00' type, but there are advantages to other types of flours - as 00 absorbs less water.

If you want to read a completely comprehensive guide to a lot of the factors, this is worth a read...

http://www.varasanos.com/PizzaRecipe.htm