Advertising in local shops is fine but promotion needs to be in as many different forms as possible because people read and see different things. For example, I read leaflets that come through the door so that works for me but a lot of people put them straight in the bin. Advertising in local publications is good - I think there are some that don't charge. Notice boards also good, sometimes schools playgroups and surgeries will let you use theirs and there are of course the shop ones. Handing leaflets out will reach some people though of course you have to have the time to do it. Posters in windows and outside buildings ... and so on!