simplistic answer
there are 2 major variables. Keyword density, and inbound links
You need to keep your keyword density for a phrase high enough for the page to be relevant to a search, but low enough for you to not be spaming
Lets say (for example) we grade a page from 1-10 on keyword density, and you page scores 2
Next we will look at inbound links, and to be ultra simplistic, lets just look at the number of different domains that point to you (forgetting their page rank)
Lets say you have 20 domains pointing at you.
Being really simplistic again, you now have a score of
20 x 2 = 40...
When someone searches, if the competition is high, google puts the search results in score order
So my page with a score of 800 will appear higher than yours with a score of 40
When you look at it like this you will realise that onpage SEO just tells google what the page is about, and about its relevance to the search. Off page SEO multiplies this up
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In the real world, in a competitive market assume all your competitors have perfect on page SEO, so yours needs to be perfect too. You can do keyword analysis of your site and your competitors, and ensure the densities are comprable
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That leaves inbound links. Yahoo site explorer will show you how well you are doing, and how well your competitors are doing. Assuming all onpage SEO is pretty perfect (thats both your competition,and yourr site), you will then find out that you need 1, 100, 1000, 100000 inbound links (depending on the competition)
I know this works. I predicted how many inbound links Ii needed (nearly 1000) and went and got them (over a period of months), and 3 weeks later I was in page 1 position 2 (my target) There is a technique in getting these links, and trust me, its hard work, and there are few shortcuts
