How frequently do you post? This is an good question, because it is very important to maintain a regular number of posts for every day, week. You will say that more important is to have good content targeted to your subject. This is very true to, but make a little experiment, post for five days every day and then look into your blog log/statistics and you will see the google crawl will come to your site every day, at fixed hours. Now this means that you will be indexed every day and if you have good content that is targeted on your main keywords you will grow in google searchs > more traffic. You can see this technique at a lot of bloggers, they post at certain hours every day and of course good content.
For example John Chow dot Com, you can see that he is using this method, and I remember that in one day his site was down and in that period of time the google bot crawled is blog and so he lost a lot of positions in searches. What I want to say is that if you post good content frequently, every day, at certain hours you will see a differance.