Here is some advice:
Don't make your profile private, you'll get less followers, because they won't be able to see your post unless you confirm there request for them to follow you.
Don't over post, or Underpost. I would only post 2 pics or 1 pic a day. Don't post like 13 in one hour, or your going to clog up someones feed. I personally only post every 7 weeks.
Follow More people. Thats the basic way to get followers. However don't just randomly follow people. Set up some cool photos and post and introduce your account in an inviting and innovative way. Meaning, set up a cool profile, with cool pics so they may think "Ok, he just followed me, but His profile is kinda cool, (Presses the follow button on their mobile device.")
_______________________________________... if you've got some cash on you, then you could always buy an app or go to a site were you can promote your account to thousands of Instagram users. However, this may be like buying likes and buying followers, I don't do that, but If you want to step up your account, and get in the game, then there is nothing wrong with giving your account an extra boost for followers and likes.
^ I hope all these tips help you! :)