How do I get more customers for my scrap metal business??

Use google maps searches. I zoom in to specific areas and then search for things like "computer repair" or "machine shop" or "HVAC" and see what pops up. Not everything will be relevant and the search won't usually provide everybody who does that but it's a baseline of people to call or visit to see about buying their scrap. And like Miked says, have your pitch practiced and have your FAQ answers ready. As example if you're calling a machine shop that machines aluminum you'll probably need a price ready for aluminum borings for when they ask. The old threads here have hundreds of tips for potential client sources btw. Take the time to read up.