Write on a specific subject, and stick to this. If you bounce around to many subjects, you won't get a reader base beyond friends and family.

Make the subject useful to the people you target to read it.

Once you do this, then start getting the word out about your Blog to appropriate sources. For example, I sometimes post links to Blog posts I have done on my Blog to here, if they are relevant to questions asked. Or read other Blogs on the same subject and add useful/interesting comments to theirs (with your Blog address listed in the header of the comment space).

There are alot of web articles on this.
Two tips are:
1.) Link to other blogs and websites.
2.) Use keywords often for better search engine results.

Check out tips in these articles:
http://daol.aol.com/blogs/tag/blog/
http://www.web-strategist.com/blog/2007/01/25/web-strategy-how-to-be-a-corp...
http://ezinearticles.com/?Top-10--Blog-Writing-Tips&id=22931

- Engage in discussions on other blogs, and where possible, link back to your blog in your comments (draw audiences to your site if they like/agree with your comments)

- keep writing your blog but find a niche in which you excel so you can become an authority on a topic.

- visit other web sites and forums that are similar in topic and audience to your target audience, and again, link like mad (as much as socially allowable) back to your blog.

- link love baby, link love. Give link love, get link love, so encourage others to link to you and vice versa.

- get listed in blog rolls, technorati, et al to be found by folks who are searching.

- use social bookmarking tools on your blog like Digg, Delicious, etc, etc, etc. (blog readers like to bookmark good information/comments/discussions, and it builds link love and page rank.

And, finally, give it time. Invest at least 10 to 20 hours a week seeking, commenting on other blogs and forums to built some repitoire and exposue of your blog links.

Find a target that you know about and blog about it. You want to be known as an expert in that area. Participate in other blogs that are related to your topic of interest. One thing that many miss when blogging on other sites is to include links to your blog and always have a signature line. Lastly, blog to provide valuable information to others.