Like Facebook, Instagram uses a feed sorting algorithm rather than have everything show up chronologically. This is great because it means you should see all the photos you most likely want to, but sometimes it means a post from a person you want to see everything from will get buried.
While you can’t control the order stuff shows up in your feed, you can get notifications whenever specific people post to Instagram. Here’s how to turn it on.
As you scroll through your feed, if you see a post from the person you want notifications for, tap the three dots in the top right corner and then tap Turn on Post Notifications.
Now, whenever they post, you’ll get a push notification.
You can also turn on notifications from their profile page. Once again tap the three dots in the top right and then tap Turn on Post Notifications.