Seo and Traffic help

I'm looking for someone with a proven SEO background to help me boost traffic. I've hired someone before only to find out that they were pretty much scammers and didn't really know what they were doing alot of empty promises. I'm also open to Web 2.0 traffic methods. The sites you will be promoting already have 7%+ conversions on them on them. I'm also open to give a % of profits based on the results of your traffic increase methods. Jules