Only one question? It's a pretty big question, and there is no single simple answer to it...

There are tons of free SEO resources on how to do what you're wanting...

Specifically, I might suggest Steve Claytones SEM Blueprint, which runs you through how to start your own SEO/SEM consulting business.

I might also recommend Dan Thies FastStart SEO guide - a 100 page no nonsense guide to SEO

Good luck

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