I have nearly 2500 followers on this blog. This is not to brag to but to bring up a larger point in that about 5% of them have regular engagement (commenting and liking). Perhaps it says something about bigger not always being better. Some of my fellow bloggers have 4 times the followers I do and have way more activity. I wonder if its the content or the person that keeps them coming back. In either case you have to offer something to keep people interested in you and what you are writing.
Sure there are case studies about such things but when it comes down to it you have to just be yourself and hope that can be the magic that draws people in. Everyone has their own sauce so to speak and the ingredients are as varied as their are recipes for this social thing.
But there is also the school of thought that one can overthink it and that is never good. Just saying.