Illustrators, photographers, and web designers have an easier time working remotely (globally) via the Internet. There is resistance to long-distance with graphic design projects (print, booths, etc). There is no explanation other than for some reason clients want to sit face-to-face with a graphic designer at least once. (This can be done with Skype but it’s still not the same.) Some kind of nervous anxiety? Client paranoia? There are many exceptions, of course. But you’ll find most of your prospective clients will be within driving distance from your studio and back. That’s about 50 to 70 miles circumference. So draw a circle on a map and see who falls within your area that you want to work with. Those are target customers.
It also helps if you have a minimum population in that area of at least 50,000 people. That is for GENERIC design work.