My blog has been running for about a year and a half. I tried some tricks or tips on promotion that I read from around the Internet. Sure, you can get some activity bursts from promotion on other places, but I've found that the number one factor for a blog is simply to have good quality content. You can trick people into visiting with clever reddit or digg titles, but they'll never turn into repeat visitors. With quality posts, the search engine and referrer inflow will be steady.
If you only blog for popularity or money, and don't really care about putting out worthwhile content, it will show, and the people will not visit your site. I changed pretty early on from quantity over quality to quality over quantity. After all, ask yourself: wouldn't you rather subscribe to a blog that gave you a great read once a month rather than a blog that flooded your reader inbox with shallow, forced posts?