You won't dabble in areas where you have little experience or interest - the very areas in which you are most likely to face a malpractice claim. One step might be to offer free initial consultations that let you screen cases for their fit with your practice, for your availablity, and for whether these are clients you can work with. If you choose to differentiate yourself on price alone, be aware that clients who shop only on price tend to move on rather than to bring in repeat work. You'll have to design your practice to allow you to attract and serve high volumes efficiently while limiting your risk with extra fail-safe office systems. Otherwise, you may be tempted to cut corners on the job you do, exposing yourself to greater liability.
Most successful marketers differentiate themselves from their competitors on service.
So every contact with your current clients is a marketing contact. Clients easily remember bad service. They also remember good service. What clients don't remember is someone who gives indifferent service. Clients can't easily judge the value of your legal advice, so client satisfaction is influenced more by service quality than by your functional capability.