Built site with 15000 traffic a day, now what!

probably Joomla(Mambo) is a good choice.

 

well, this program - XSitePro, is a good tool for optimizing content. It names the images on your web site after keywords related to your website. It writes useful content that people would want to look at, updates the content frequently (Google likes new stuff) which prevents your web site from being sandboxed.
it does a great job with regards to the content optimization.
First we have to understand that Search Engines are blind. They only see valid HTML codes. This program makes sure that the page has a valid XHTML, because search engines find it easier to read valid codes.
It uses for example h1 for the most important title and h2 for the name of the second important and so on.
The title of the page is important that is why it puts "name of page" followed by "name of site" and not the other way round. If you're doing it manually, please make sure that the name of the page precedes the name of the site.
It puts the content of the page at the top which is more valued by SE.

 

Complete support goes to Bombaywala,

Great piece of advice and probably it is now high time you chose a path to follow wanderingmind. I guess the steps, described above, are just those successful ones that you need (with a certain degree of probability, of course ).