I worked there for about six months. It was fun. Most of the time. Can be stressful too. Learning everything in the beginning can be VERY DIFFICULT a month or two.
Some people make very large orders and will not tip you. You will be upset but do not despair. It'll be fine.
Some will tip more, some short trips will tip a ton. It averages. you will like work at Domino's but it's not for building a career, go there - make some $$$ and move on.