I love this post from Zen Habits called, Haiku Productivity: The Fine Art of Limiting Yourself to the Essential. The post offers several ways to focus on the most important tasks and includes ways to ensure you don't waste precious time.
One of the suggestions is to limit yourself to 10 RSS feeds. Interestingly, I just went through and unsubscribed to a bunch of feeds last night because my list had gotten too long. I don't check my aggregator when I travel and often come back to hundreds or thousands of unread posts. I did not get to 10, however, I still have over 100. I think I should shoot for 50. Emphasizing this suggestion could well bite me in the tail - I guess I will just have to see if my subscriber numbers go down!
Check out all the suggestions. In the spirit of focus, try just one!