Choose a specialty that you may be familiar with and target that particular specialty with your marketing efforts. For example, if you previously did the billing for an orthopedic doctor, target your marketing toward other orthopedic doctors. Staying within a specialty will make things much easier for you as you get started. If you are looking for a relatively easy field to enter, look into mental health billing. There are very few codes to learn, patients return regularly cutting down on data entry of new patients with each visit, and you learn the little issues for that particular specialty.