In order to sell yourself properly, you need to make sure that you are qualified adequately. To be a pharmaceutical representative you will generally need a bachelor's degree in the field, though some may employers may require that you have an MBA. You also have to be willing to learn a lot of new things and be very flexible. You will need to have a background in science, and that means that you will be constantly working with science. If you are one of those people who do not like science, then this is definitely not the field for you. You will be utterly miserable.
It is also important to keep in mind that while practical experience will definitely help you, most companies will not hire you based on that alone. You must be able to work with people. As you probably already know it is impossible to learn people skills in a classroom or in the work place. These are skills that need to be developed on their own, and while you can be taught how to deal with people, you cannot be taught how to seem sincere.
When you do this, you are essentially on your own. There will be no one around to motivate you, and you will have to do things all on your own. You will make calls to hospitals, doctor's offices, and HMOs trying to sell your product. It will get very repetitive after a while and you will have to find a way to keep yourself going. Everyone has some way to do this, and you will have to work hard to find your way. This is the reason that not everyone can do this job. You have to possess a certain level of stamina in order to do a job like this.
If you can do this job though, it won't be without its own benefits. The annual salary for someone working in this field will be about $56,000 per year. You won't be getting incredibly rich doing this job, but you also won't be living an uncomfortable life. If you can deal with the fast paced work and the science involved, then this is definitely the job for you. There definitely isn't anything better than working from home, setting your own hours, and being your own boss.