...is to use great titles. Seriously.
Here's an example: Steve Rubel's "The Web 2.0 World is Skunk Drunk on Its Own Kool-Aid" rant caught my eye yesterday because of its great title. After reading Rubel's post, I added it to my link blog, where it was spotted by Steven Hodson. As Hodson writes, he unsubscribed from Rubel's feed a while ago, but he just resubscribed based on the strength of that one post - and I'll wager that the post's title is why it got his attention.
As people subscribe to more feeds, the more they stop reading every unread item and instead just skim the titles looking for something that interests them. If you use boring titles for your posts, skimmers like myself are likely to skip right over them.
In addition, once people get used to reading feeds, they start subscribing to link blogs and search feeds which aggregate content from all over the web. People who aren't subscribed to your feed often find you through these aggregate feeds, and it's the strength of your titles that leads them to read what you have to say.
Now, I'm not about to recommend using sensationalist, "National Enquirer"-like titles - that would just pollute your name/brand, leading people to unsubscribe from your feed. But descriptive, catchy titles get the attention of readers who might otherwise never see your words of wisdom.
So if you're going to take the time to write a blog post, make sure to also take the time to give it a good title. Yeah, I know that sounds painfully obvious, but a quick glance of your unread items should provide plenty of examples of interesting posts that go ignored because of lousy titles.