I checked my rankings on Google.com, Google.co.uk, and Google.ca and the site that is first on Google.com is also the first result on all of these pages for a lot of niches. Now my sites are on the first page of google for most of my niches, except for .co.uk and .ca my sites are scattered and are not ranking well! This makes sense, but how much? And how can I improve my rankings for other countries?
If you want to see how UKs are seeing your site, search your site with UK proxy on. You may have already ranked well in their eyes.
This would make sense. Especially if you lived in one of those other countries and a foreign site was ranked better that non foreign sites.
It could also be that while in your google webmaster account you have set your geotag to unlisted, your competitors in the countries you aren't ranking well for have set it to their specific territories. This may or may not give them an advantage. Just a thought.
you better go to your "google webmasters" account and choose your geo country, letting it default will make google to choose your better google results rank.