Instagram is helpful especially if you are more visual-oriented. The tagging system helps although the algorithm can be kind of shitty. Beware of art thief and reposters who sometimes give no credit, though; although it's never happen to me (my art is too ugly to steal) the regulation is somewhat crap.
Step one is to follow people you know and interact (liking, commenting, doing shout-out), the more you get engagement on post the more chance it get featured by algorithm. Use relevant and trending tags to gain more exposure, and tag people if necessary. Adding location can also help.
Instagram is moving on a fast pace, you need to post oftenly and consistently to get a following. Followers number often fluctuate and it's normal, some are bots or just people wanting to be followed, don't be disheartened if you're unfollowed out of sudden. Don't fall with follow for follow bullshit unless it's a friend or a trusted person, good chance they'll unfollow you as soon as you follow them.
Consider getting a business account for followers and engagement insight, it also can be connected to your Facebook page or you can claim a mew one.