Post REGULARLY. Posting often is important but not nearly as important as the regularity of your posts. If you don’t have a lot to write about, post once a month. If you have a lot of things to share, post two times a day. Perhaps to start you could post something once a week. Be sure you always post new content on the same days if you do it weekly/monthly and around the same time if you post daily. Readers get frustrated when they check back on your blog expecting new content and discover you haven’t updated in a while. Similarly if they check back expecting just one post and you have five, they feel the need to check back more frequently. Then you better live up to your own standards or they’ll go back to being frustrated at the lack of fresh content.
To help with your post regularity, write posts in advance and schedule them. I’ll add a website below that explains how to save posts and set a time for them to publish later. This comes particularly in handy when you don’t have a regular schedule or you like to write a bunch of posts in one block of time.
Get your links out there! There are numerous websites that catalog blogs. Technorati.com and del.icio.us are two popular ones. Search for friends who have similar interests and build your network that way. Similarly, find other blogs that are complementary to yours, contact the writer and suggest a link exchange. Sharing readers is a great way to get the kind of traffic you want.