Exclamation How can i get better results on serp?
 

I am using magento 1.6 and all my category pages has title and meta descriptions with my keyword(s). Also i have category descriptions written all fresh by me with including h1 tags. When i check my category pages, home pages and product pages i have good report back from firefox SEOquake and other tools. But when i use my keywords to search on google i am not coming on even on first 50-70 pages. I also have fresh content on my home page linking to category pages including my keywords. And i have robots. txt file and sitemap too. My robots.txt file is
User-agent: *
Disallow: /js/
Disallow: /images/
Disallow: /css/
Disallow: /install.php
Disallow: /LICENSE.html
Disallow: /LICENSE.txt
Disallow: /LICENSE_AFL.txt
Disallow: /STATUS.txt
Sitemap: mydomain/sitemap.xml

What else should i do to get better serp results on google.co.uk? Also on this robots.txt file i added my sitemap but is that mean i am blocking google to crowl my sitemap?
Keywords that i am using not easy to get good serp results because they are really popular keywords but least i want to be able to get on first 10 - 15 pages.
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