Hi there. It'd be interesting to see your website to judge what might work nicely with the blog, but unfortunately it seems to be down at the moment. No worries
My advice would be to do all kinds of things. Coding tutorials and sharing best practices would be great. Also videos and images showing how the game's developed over time, perhaps. Stories about what you've learnt during the process would make for interesting reading. I tend to go for business-type blogs as well, about how the games market's been changing, and how different approaches to marketing have affected sales, and so forth. I get the feeling that tends to be a bit of a niche interest. Opinion pieces on game design would also go down nicely, perhaps.
Ultimately, I reckon you should try to do everything you'd enjoy writing about and see what people respond well to. I think in most cases people will start following a blog if there's one article they like on it, even if they don't take an interest in most of the others. I also tend to follow blog updates through twitter feeds rather than RSS. Maybe that's just me though. But it's worth keeping an up-to-date twitter feed that points to the blog.
Also, make sure you enjoy writing it, as that will show off in your writing and in the way you interact with your followers. So do stuff that you enjoy and that shows off a bit of your personality
I don't get a lot of followers on my blog, but I like to have it because (a) it helps me organise my thoughts over time, and (b) it's there for people to stumble upon, and if they enjoy reading it they might be interested in my games too. So if I send off press releases, for example, I can give a link to my blog, and recipients can take a look at it to see what I'm all about. I don't see it as a promotional tool in and around itself, just part of a network of stuff I'm putting out there to sow the seeds of interest
Hope that helps - it was a bit rambly, and I should probably get some sleep