I am also in that same situation to really increase the numbers of my followers and also to make them crypto related but I dont even know how to go about it. If you can help, I will so much appreciate... Thanks and Op you need to take advise...
What I do is to regularly check for twitter related threads on bitcointalk. Yes, I use the search feature, you could do too.
Some threads are about twitter services (post this and get satoshi), some others are about people trying to increase their number of followers.
In both cases, I got all those accounts one by one and followed them. Quite a lot are nice and follow back.
Now, since obviously nothing is for free, I also installed a twitter add-on and from time to time I see who is not following me back and I also unfollow.
Another useful thing to do is to tweet. Not too much and not too off topic, since people will mute or unfollow you. But if you can get this way some extra followers (which you should obviously follow back).
Yes, it's hard work, but it's the only way I know. I hope it helps.