I think everyone would like to decrease bounce rate on their sites. :)
You could do this via offering in need contents on the landing pages just like what you have put on the referral pages or ad links. Having a professional designing for your sites according to your niches would be helpful, too.
A great site to check out to help decrease your bounce rate is a site called feng gui. You can take a snapshot of your homepage and it will show you how someones eyes will navigate your site. This helps to determine if you may be lacking in some areas in which you want your visitors to see like certain links to your other pages.