How can I get more followers on Instagram?

I have done a lot of research on building an Instagram audience and getting more and more followers, and what I learned is, you actually have to get engaged with your audience type. Let say your audience type is movies, so you have to engage on other pages on movies and engage with other users whose interest are same.
Simply interact with them through comments and help them in a meaningful way. This way, you gonna attract so many followers. There's a popular technique, I actually don't remember the name of it, but it exactly explains the same I did here.
So I hope it will help you.

The easiest way to get more followers on Instagram is to use an application wherein you can automatically get many followers each day. However, I don’t recommend using this method because not only will you get more followers each day, but you will also automatically follow random people’s accounts. To top it all off, you would be following bots accounts or people from other countries who do not use the same language as yours. Of course, you can unfollow these accounts but it will eat your time and it’s not going to be worth it in the long run.

If you wish to do the normal way to get more followers on Instagram, you can use several popular hashtags such as #instafollow, #FF, and #followback. You can also post pictures that are relevant to your target audience. For example, if you are a traveler, make sure to post pictures of your travels as often as possible with hashtags such as #tagsforlike or #photooftheday.