I'll copy and paste what I just told someone else who asked that same question...

Hey there! Hmm.....read..read a lot. Read how to make posts. Follow people and give up votes and comments to the posts and comments that help you. You get things off Steemit that you don't get from Facebook and Instagram or any other social media outlet, so have fun with it and enjoy it! Post what you love, and the people who love the same things will follow you. It takes time...I wouldn't consider myself successful on Steemit, but I'm working towards that one day at a time!