In my business, I work with over 160 business in town. A lot of my correspondence with those business' are either by email or text/phone. All business owners seem to never have enough time, so I just figure out which is the easiest per business owner and go from there. If you are starting from scratch, start with a simple hello email. See what happens and follow up with a phone call. I believe you are selling yourself as much or more than your business. Make a friendship.