The best method of getting followers is when you earn them organically. This means followers you got as a result of network, outreach, posting, and engaging with the post of others.
The followers usually, would be earned without them being forced to follow you. Because they have a genuine interest in what you post, they engage with your content and as such, you have a better chance of getting popular if you get more organic followers than buying them or getting for free as discussed in this article.