Hot water will help you to get a very soft tortillas, so, dont forget to heat your water in microwave oven or in Stove. I heat in Microwave oven for 1 Minute.
You need to let dough balls to rest, so you can stretch them without problems.
The pan should be hot before you put the first tortilla. What I do is to put my pan to heat at high temperature and when is hot I reduce temperature to medium- medium high.
Remember your dough should feel damp and somewhat sticky. Do not add too much flour when you are shaping the tortillas.