If you want to enhance your website traffic for specific keywords or phrases then you start doing off page optimization such as blog, forum posting, rss feed submission etc.
It's the same across the board, it doesn't change for competitiveness. However, I do make sure all my web pages have "optimal" on-page optimization before working on building relevant quality backlinks with the proper anchor text.
To compete high competition keywords, the following are my experience thoughts- The perfect on-page optimization is must A solid strength of your website (number of pages) Massive link building in organic way No Spam High PR link creation
I don't agree that it's the 'same across the board'. For low competition keywords you can get rankings from very simple techniques such as forum signatures, blog commenting, articles, etc. For high competition keywords you need to do all of that and more. You need to focus more on getting links from high PR websites. You need to check what the competition is doing and do it even better.