Search engine keyword optimization is more so a function of off page factors and on page factors.  Most websites that do well in the search results are ranking well for natural search terms because of both on page and off page factors.

It is possible that a website that just creates pages and optimizes page elements or code may rank very well for keyword phrases that get little traffic.  If you have been chasing long tail keywords or phrases you already have discovered this is not difficult at all.

When ranking well for competitive words optimizing your website just for keywords, code and other factors such as keyword density may have little effect.

You have heard the phrase that ‘content is king’ and there is truth to that because if you have enough content on a well indexed page you may soon discover your page or site ranking for keywords that help your conversions and ones you may not have considered.

Now the truth is if you want your site to have a chance to rank well you need back links, links with anchor text that is keyword links pointing back to your site.

There are several ways to get links and it seems the most popular way to get links is through article marketing. That is writing articles and submitting them to the more popular directories. This seems to be a very effective method.

Another effective method is leaving links to your sites in forums. Most forums will allow you to have a link in a signature of you post or in a profile.  You do not want to be too aggressive with this method it will be looked at as spam and likely get you banned or at minimum a firm warning from a forum moderator. Though many forums have no follow in the links even these links can generate traffic.

What is of value is forum links that have a follow link with some page rank.

Now we have talked about inbound links to your page being very important with competitive keywords or phrases.  Content is still very important.  What your best strategy is to develop inbound links or backlinks back to your site for the natural keyword phrases you want your site to rank for.

I will leave you with a link to an article that was posted several years back but still holds true today.

http://www.seo-news.com/archives/2004/oct/7.html

Keyword density is the number of times a certain keyword or keyword phrase is found throughout a page compared to the other words of text. A little will go a long way. There is a big difference though when working with very competitive keywords or niches and more on that later.

If you’re an avid writer it is usually a good idea to start with a keyword density of about 2-3%. There are free keyword density checking tools available but more on that later.

From my own observation and testing for most niches and article writing 2-3% is a good start when writing articles over 250-300 words.

If you are going to write without using a tool write naturally and if it is a 300 word article at most use the keyword phrase 6-9 times. I world always stay at 2% when writing an article without research so in this case 6-7 times would be my recommendation.

Always use the keyword phrase in your title and always lead off with your phrase within the first few words of your opening sentence. Then spread the rest through your article and save one for the last sentence.

Now when going after very competitive keywords or keyword phrases it is a good idea to check out density. I have seen keyword density on web pages on search engines first page of results up in the neighborhood of 9%!

Once aware of this higher density for certain competitive keyword phrases I started writing articles and sales pages with similar keyword densities that were commonly found on the front page of those search results and found that it was much easier to get on the first page of the search results.

The free keyword density tool I use can be found as a plug-in for Fire Fox and comes with a suite of other tools and is called SEOQuake. The keyword density tool built into SEOQuake will return all the keywords and phrases broken down into a percentage as a keyword density.