It's surprisingly simple to make tortillas from scratch. You'll need to pick up a bag of maize flour before getting started; you can find it at most supermarkets and of course at Mexican food markets. The maize is mixed with wheat flour (self-rising if you have it, otherwise not), seasonings, and hot water to make a dough. To form the tortillas, you simply divide up the dough, roll out thin, and cook in a dry skillet.