Instagram is one of the best social media platforms for artists because all of the posts are visual. This is a dream come true for artists who don't want to write much when they post content to social media. In fact, people who post longer posts can disrupt the viewer's experience of flipping through Instagram's images and I don't recommend it.
The exposure that your art can get on instagram follows a word-of-mouth model, it is organic and unforced. People who like your image spread the word simply by liking it since people who follow them will go to their "following" tab and see what they have liked recently. But sometimes the sharing is less passive than that if people love your work and want to introduce it to someone specific who they think will also love it then they sometimes comment below the image with @someone'sname. So people discover your work in a natural way and all you have to do is post interesting photos of your art and inspiration...oh and connect with people. It's social media after all, you can't exactly thrive in a bubble of one.
What to consider when using Instagram. Some artists really like to control the look of the content they post on Instagram because the images work together and they want to present a seemless style. Others, and I think I fall into this category, post pictures of our art, the studio, friends, outings and the occasional joke. You decide what you would prefer - there isn't a right and wrong but a few photos of you or your studio every once in a while can really give your work context in the eyes of a potential buyer.
Since Instagram is still a very "social" media it's important to reply to people's comments on your work and repay the favour. You can make fast friends with artists in other cities across the world this way. My experience with Instagram has been great and I've found it the most organic place to connect with other artists. Perhaps its because we are communicating more with images on this social media platform but Instagram feels like home for visual creatures.