I am certainly not a social media guru but after looking at your Twitter account, I'll tell ya what I think anyway!
You're driving all your followers to other people's sites via retweets and links. The only link you've got to your site is in your bio, which is important, but you're not giving anyone any compelling reason to check out your site. If you followed me, I would check out our site once (when deciding to follow you or not) but that would be it.
The link to your site in your bio goes to a single post too instead of the home page which is odd.
If you want people hitting your site, tweet about it! Don't pound people with repeat tweets though. I just unfollowed a person today because they tweeted the exact same tweet repeatedly over a few minutes.
Again, I'm no social media guru but I have some thoughts.