The first thing you should do is sit down and talk with as many real live reps as you can. Ride a day in the field with a rep, too. You'll learn firsthand that the job is not all peaches and cream.

You should be very familiar with what you are getting yourself into. It's like any career choice - you need to not have merely a good idea of what the job is about, you should have a working understanding of what a rep does.

The other things you should do is examine your motives. If you're looking for big money fast, this is not the job for you. If you want to be continuously learning and training, this might be up your alley.