I have found that google is more difficult to rank well for than bing/yahoo. I also have 2 sites and 1 ranks better than the other in google.
From my research, google requires a more broad approach than the others. Make sure you comment on wordpress blogs, submit articles with backlinks to article feeders like ezine.com, have good external links on your site, constantly update your site with new content ( blog entries ), use social media, bookmarking sites like digg and stumbleupon, have high traffic sites and high page rank sites that link to you, comment in forums with dofollow links... Etc etc.
In summary, it is very difficult and time consuming to learn and execute the process. It is worth the effort. Probably why seo
companies charge so much.
There is no easy way. Don't be tempted to buy hundreds of links at once. Look up black hat seo
on google, and understand the things that you cannot do, else you will be blacklisted.
Hope this helps.