Thermostat Help

Ever since moving into our new house, Jen and I have been trying to figure out our thermostat. It's one of those newer digital ones and we are just confused as to how it works. It seems that when we set it for a specific degree, it will get way to hot or cold in our house. For instance, if I set it on 70 and look at it a while later...it will still be running but says that it's 73 in the house. I think the degrees are a little off...because 73 makes it too warm in our place!