Also been in business about 28-30 years.I have been in business 28 years, my first year I tried this and I got nothing from it, waste of time. Do great work and your work sells you. I think it took 3 years before I could take a regular pay check.
When I started on my own, I would find a busy looking company with an old (usually crappy) and or broken sign. I would then bring in a mockup printout, made on Corel 4ish. They didn't get to keep the copy without a deposit and I had a price ready... I got jobs. About 40% of the time they went for it.... 60% free design work but better than 0% jobs.