Market yourself to fabrication shops and do some market research on pricing, undercut by a small percentage. Read up on common standardized and even industry blasting procedures (aerospace, military, depending on what is common in your service area) and be willing to broaden your scope. Find a good source for media and parts. Be professional, and be realistic with your lead times. Dont change quotes, unless they did not disclose something critical. Think long term. Peanut butter jelly time.