One good tip to increase traffic is to think ahead - quite literally.
At different times of the year, search volume spikes markedly in different categories. There are the obvious times of year, like Christmas, when people search for gifts, or Valentines Day, when people search for flowers and chocolate.
You can use Google's Trends tools to do some research.
Those of you who can get news items into Google's universal results, via blogs and feeds, can do well following this strategy.
Darren at Problogger has quite a good post on this:
Don’t Miss Seasonal Opportunities on Your Blog for Spectacular Traffic. Read to the bottom of this post for an example of how I’ve used the same content three times in 18 months to generate 50,000 page views on one post.