How To Keep Readers and Gain Subscribers

Hey, BHW! Got a question for any of you out there that run a successful blog. I know that content is a great way to keep readers interested and subscribers gained over time. I've done that, but, I'm wondering if there is anything else I'm missing in order to increase the number of subscribers and readers of my blog. Are there any uniquely legit incentives (aside from the usual "LIKE MY FACEBOOK PAGE TO WIN THIS CONTEST") that I can offer my current readers while still serving and catching the interest of new readers?

Any and all suggestions would be helpful, thanks ahead of time!