So I came across a post from Instagram recently which explains how they rank posts. It was interesting so I thought I would share it here since others might also benefit.
How they decide to show you content:
They look at five interactions: how likely you are to spend a few seconds on a post, comment on it, like it, save it, and tap on the profile photo.
They also add that story reshares of your post are great and now also a signal to the algorithm.
This means to get your posts seen you need to think about what would make people:
1. Take time on your post
2. Comment on it
3. Like it
4. Save it
5. Tap your profile
6. Share to their story
You can read the post here https://about.instagram.com/blog/announcements/shedding-more-light-on-how-instagram-works