You are wasting your time by putting on one advert on radio. If you are a trades person, you may find it to your advantage to wear a neat uniform with your logo embroidered on it. Professionals such as lawyers, accountants etc. will benefit from producing a periodic newsletter. This could be at quarterly intervals or even yearly. In many professions, a syndicated newsletter can be bought and the letter sent out to clients under your own letterhead.
Shops often have carrier bags made to order with the shop name emblazoned on the side.
If your business is specialised enough, you should consider producing a brochure to describe your services. You could capitalise on this fact by asking your existing customers to recommend you if they have been satisfied with the service.