When you are linkbuilding make sure they are optimized. I have created a list of things to watch out for. You may also want to go through your existing backlinks and re-optimize them, escpecially if they are from pages with good pagerank. This could be time consuming, but will be worth it for your better links. http://hubpages.com/hub/27-Ways-To-Optimize-Your-Websites-Backlinks