Consistency (and thereby lack of it) and relevance of content are the two most significant factors that determine short- and long-term viability of blogs and websites. We like fresh content, but we also like to know what it is we're looking at and why it's relevant. If possible try to aim for one post every so-many days. Do whatever is feasible, but keep the frequency count consistent, otherwise people drift elsewhere.
Agree with previous poster also. The number one driver to your blog is great content. Forget SEO. Great content delivers the same, if not better results than SEO. The more people that link, cite, and refer your content, the more you'll move up the ladder.
I look forward to reading your blog!