i dont want to force or fool anyone into following me unless i deserve it so i just tweet regularly with those gamedev hashtags that get automatically retweeted to people subscribing to them and those who stumble across those retweets and find them interesting end up following me i guess
make sure you're making something that's actually worth following i guess :p
get enough followers and i guess you can start directing them to other portals maybe (patreon?)
i haven't gotten there yet and rightfully so – my game has a long way to go still before it deserves that – but nonetheless i do get a few followers every day i post updates
no rush. unless your game is rushed. gotta prove yourself and your game first.
EDIT:someone just tweeted this. might be relevant to you:
http://www.binpress.com/blog/2015/02/06/indie-game-launch-guide-pre-launch/and this which is only partially related: http://www.gamasutra.com/blogs/ColmLarkin/20140611/219126/Getting_Your_Game_Greenlit_In_2014.php