Twitter and Facebook are definitely one solution. You are on there anyway (well, most of us) so it is easy to mention the link and find an audience of people who are already interested in what we have to say. You may even consider facebook ads. You can spend as little as $1 a day to get your ads in front of stranger's eyes.
Another advertising option I am trying is Project Wonderful. You can put as many boxes on your blog as you like to create revenue, then spend that money on other blog's ad spaces. It is $5 to start. I paid my money a few months ago and have not had to add funds.
The one suggestion I have not seen work is the theory that if you visit other people's blogs and comment it will drive traffic to you. It is a lovely idea that I would love to make work.
What do you do to bring eyes to your blog?