Organically growing your Instagram audience base is the way to go. There are a variety of ways you can get that to happen. Some of the methods include positing high-quality and engaging videos and pictures at the right time. Engagement with the posts of others by liking and posting interesting comments.
You can also share your Instagram username anywhere you have the opportunity and let interested users follow you. You also need to be patient except you have the marketing budget to market your brand.