But most businesses do it wrong. Radio does work for most businesses if it's done right.
Here are some mistakes:
1. Not advertising long enough. You need to commit to at least 3-4 months before ever expecting to see any sort of return from your advertising. NEVER expect to see an immediate return from any marketing effort.
2. Relying 100% on radio. There should never be anything in your business that you rely 100% on for customers. What happens if that goes away? Radio should be a portion of your overall marketing effort. Make sure that it all aligns towards the same purpose.
3. Not running enough ads per day. You cannot expect to receive traffic from 1 ad per day. Many times I would rather advertise 5 times on the same day than just once each day of the week. Repetition is key.
4. Not staying focused. Instead of running an ad at 9am and 4pm, trying running them both between 2pm and 4pm. Again, repetition is key. It takes quite a few repetitions before folks are moved to take action.
5. No call to action. What do you want your customer to do? Visit your site, call you, sign up for something, visit your store? What ever it is, make sure you tell your future customers what you want them to do. I'm lazy, but if I'm pushed, I'll do it.
Always think through any marketing effort before you launch. Never launch without a plan.