I always start SEO for my own sites by keywords analyse in google adword tool , then track the keywords of site of my competitor , finally once i have my own list , i embed them into website , to the Title , Description and Keyword , on the Description part , i make them varied on each inner page. Also do some new content on website to match the keyword that i set. That is in SEO called Onpage Job , the next step you can do the off-page , starting to submit your site to all search engines (not only google) submit to web directories in the correct categories , submit url with short fresh articles in social bookmark like http://delicious.com/
, the finally start to submit 300-500 unique and qualified articles to Article website like http://ezinearticles.com/
some is free , some you can pay for faster moderated and published. In this final step that i mentioned , most of SEO companies or Agent , they have their own web or blog (wordpress) to submit articles for their clients. You can also have your own but that need a budget.