Search Engine Forums, SEO Forum

You've got a fierce competition for those keywords, you'd need to build a lot of popularity to be able to compete with them. Then improve the on-page optimisation of your handset pages, as it's all about a table with the tariffs and an image of the handset at the moment. It'd also help if you implement a mod_rewrite on your URLs to make them static. And pray, as it won't be easy, since you're competing with big and popular sites.

While selecting keywords it is important to do a proper research. Research helps in finding targeted keywords. While doing research thing according to users which keyword they may use. Like this way you can easily find out targeted keywords.