The site I'm working has numerous PR7 and PR6 pages and over 300 backlinks due to it's age. However, it doesn't show up in any of the 3 SE's on any valuable keywords. I'm planning on setting up more links within the site that use the keywords we're aiming for. Will that alone start to help our rank? or should I also look for more links on other sites using the keywords?
in the process of doing that, there weren't even unique keywords and descriptions because "they're not weighted much". I'm also going through and getting the keywords into the headline tags etc
Once you have SEOed the site and have pages optimized with your keywords. Get additional links to those pages using the keywords in the anchor text.
The site is most probably experiencing some sort of a penalty if its properly optimized yet not ranking.