In my opinion, your difficulty is also your advantage. You can approach the shop owners easily at the first time, of course , in the role of a customer. On the contrary, they will be honor to get in contact with you. When the relationship becomes near and dear, you can invite them to buy your goods/service. The most important thing is the way you communicate, do never let them have the feeling of being cheated. If you have tatent in communicating, this will be very simple. If not, you can attend in some communication training courses, where you will be taught of how to get the heart of other person.
Besides, you should always keep on your mind the sentence "Don't be afraid of being refused". Keen on your target, you will get the result.
Good luck !!!