I have a very engaged twitter following in a targeted niche. My followers love me, always telling me how amazing I am, retweeting and favouriting me, we chat to each other, I ask questions related to the niche and they love to respond. I have social oomph set up to tweet all day, every hour or so in amongst all the chat and stuff I post an 'ad' linking to my services. People will retweet it and comment on it but hardly anyone clicks on the link. I make around 1 sale per day from it. Any tips on how to get more people clicking my link or what type of ads work best?