There are other ways for you to do this; but most other businesses don't even use these ideas. So if you do just the three things listed here, you can grow your African business faster than most others.
1. Ask people. End each sale by saying "Thank you. I hope that you will tell a friend about this!" Happy customers often love to support you. You just need to remind them ... and say thank you.
2. Give customers something to talk about. Give them something that they can give to someone else. It can be a flier, a coupon, or an advertising specialty.
3. Make it easy for your customers to talk to even more people about you. If you give someone five samples, some people will look for five other people to give them to.
There are a lot of other things you can do to get more word of mouth advertising. If you only do these three things though (and do them regularly), you will get the most results fastest. Make sure you are getting the easiest stuff done before you try doing more time consuming tasks.