Twitter can be a tricky business when it comes to promoting your direct sales business. The basis of Twitter is communication and getting to know people. So you need to start following people and engage them in conversation. How you do this can be done in a variety of ways and there is no right or wrong method.
For me, I follow people who are local to me (to help get parties), I follow people who are in North America (sales and recruits), I follow marketing people and I follow many others for a variety of reasons. But, I do not just post about my business and how they should buy my product. Some of these people I will never interact with due to the fact that I follow them for their knowledge, but there are many that I potentially could interact with.
I will see someone posting about a bad accident in the city, and I may reply, thanks for the information, I was just heading out that way. Or, I follow some crafters, so I may post a picture of a project I just completed, or comment on a project someone else completed. This builds up a relationship and trust between you and the other person.
I do post the occasional business post. Typically these are posts that come from my blog, as I have my blog set to cross post to my Facebook and Twitter account. Sometimes they are posts from my fanpage as this cross posts to my Twitter. But I bet if you looked at my Twitter feed, less than 15% of my posts would be business related.