Soil conditions will dictate what type and how much base you need. Six sack (commonly called 6 bag) mix is required in some areas. Especially for concrete that will be on City property such as the driveway approach. It is 6 bags of mix per yard of concrete. The reason it is required for approaches is that it is very strong and it lowers the liability for Municipal vehicles that may turn into your drive. Places I have lived require it for the approach but not the whole driveway. One other thing I will mention is to think about the future. If you think you will ever run a water line that will cross the driveway, install a piece of pipe that is larger than any line you may run later, under the drive to use as a sleeve for the water line. This eliminates digging under the concrete at a later date.
If you have never made a mistake, you haven't done much.