Here is the things you can do to succeed on Instagram :
- Find a niche, if possible, always works better
- CONTENT, create valuable, unique content, and above all, create a story and some values, most of the time people will hook on a story or values, not on simple images
- Post a lot of insta stories, it will reinforce the link between you and your community
- Bot, slowly and the more targeted as possible, to gain visibility and followers (my favorite is Jarvee)
- 2 or 3 times a year, do some giveaways and contests
- Create some partnerships with people in your field and share visibility
- Send DM's (no spammy dm's, be creative and find an interesting way to start a discussion with people)
- Buy some ads, or sponsor some posts, get some metrics from a tool like socialbaker and sponsor the most valuable post
This is my personal experience, hope it will help

i own a digital agency (8 years old) and i had the time to try a lot of different things
(And sorry if my english's not so good, i'm from France, cheers!)