Let me let you in on some thing that I realized.
People love contests!
I think that if you do a contest, week long, but with posts talking about different aspects of it all week, then you will get more people. Interacting and upvoting comments/posts will help, its important, but its slow.
What you want is for a whole bunch of people to start resteeming your posts and trying to win a prize!
Get creative and think about something that could have a daily update, or a rolling prize where you could have a winner or more each day...
The #contest tag is where it is at.
Just my two cents! If I have any other ideas I will let you know :)