@upvotebank and @minnowsupport are a good start. The rest is advertising to be honest. Not everyone that votes for content actually read it. You can buy votes which then actually attracts real readers to the blog. I also post the link on Facebook and Twitter as well as a link on my Instagram.
If you want to buy votes to boost visibility checkout @Smartmarket and @minnowbot.
A lot of people who sell votes look at what they auto votes for so it helps build followers.