Best thing to do is play other people's games and leave them feedback on their game page. That's how I've received most of my followers.

Hello! There are far better people with far bigger followings than me to advise here, but best route to followers is ultimately through great games and regular updates/content relating to them. There aren't too many short-cuts here, sadly; people follow when there's value to be had. Consistency of communication with meaningful updates is key on that front. 

Some other strategies that might work for you in short term, though:

• Put some effort into your itch.io creator page - let people know what you're all about. Treat it like you would your store page; sell yourself! Make it look nice, use formatting, use imagery, include links to your website/social media etc. 
• Become a vocal part of itch.io community - be present on the forums. Join the chat on Discord. Have an opinion and help people out with their projects with any relevant knowledge/experience you might have.  
• Cross-posting - somebody mentioned already, but engaging with other developers and their games will give you some degree of follow-back. Interact with others with reviews, ratings and comments, and you might see a boost yourself.
• Promote outside of Itch.io - be sure to promote your Devlogs on Twitter/FB/IndieDB -- wherever you might have a studio presence. Syndicate your content across these other platforms where you can, and leverage existing followings you might have elsewhere. 

I hope that's somewhat helpful. I've also chucked a follow to everybody in this thread so far and will continue to do so :) 

Mostly just agree with others in here, especially playing other peoples games and interacting with other creators.  :)

Chucked a follow your way just cause your having a go!

It is hard just starting out, i'd know, because thats where i'm at as well!  xD

Have a good day and good luck with getting followers!  :)