You market your blog by writing material that other bloggers want to quote and reference. Thirty posts is actually not very many. I have two blogs that are nearly three years old and have more 2,000 posts on each. I have a couple of others with somewhat less.
I actually think that there is a critical mass in the number of posts ... around 100 or so.
To get noticed by other bloggers, start quoting THEM in your blog and remember to give them a trackback. They will notice the trackback and follow it back to yours. You could also email them to let them know that you qoted their material.
How good is your blog? No, really, be honest - if another blogger in the same area of interest found your blog would they think 'I must link to that, my readers would find it fun/useful/informative'? If your blog is that good then start quoting other bloggers posts and putting your point of view. Bloggers will always find blogs that link to them (through Google and Technorati) and if you have a quality blog then they link. Also comment on other bloggers posts - they will check out your blog by clicking on your name.
If your blog isn't likely to be an object of admiration to fellow bloggers then get an entry added to blog directories - but beware, the people assessing your blog for inclusion are pretty savvy and know the difference between a real blog and an attempt to earn advertising dollars.