Also if you're not bothered about ethics, only about performance then you're pretty much guaranteed that a search on "seo consultant" will return the best seo consultants. Depending on your target region you may want to check a different SE, Google for UK, Baidu for China, Yandex for Russia, etc.; in some areas there's a reasonably split or indeed to test the SEOs effectiveness then crossmatch on 2 or 3 SE.
As dcnstrct says it's about onsite and offsite optimisations. On site is a technical process largely, off-site is a vast art as broad really as marketing in general.
this is pretty much the only subject where, by definition, the google search gives you the best results.
Many people can help you with the fundamentals of getting your site together but most of the action is in marketing your site and frankly, having a good site and product that people want to talk about.
Beware of tricks and claims of performance. Many people can do things to manipulate your ranking in the short run but you will be punished long run. Think quality content and alignment with your target audience and you will be fine.
1. Creating exceptional content that is "rank worthy" and that people will link to.
After you've created great content, if you've got time, then do the basics to make it easy for search engines to find that content and index it.
However, if you build that content all in flash, setup your robots.txt incorrectly, or any of a number of other technical snafus then you can screw up your rankings. Hence why it is important to be setup in the right way for the search engines to find you. Otherwise you will miss out on on most of the traffic.
I've done full SEO campaigns with larger budgets and currently manage millions of paid media on search engines and other places.
(1) They guarantee results. (2) Only take a 5% commission till results are achieved, and maintained for a period of time. (3) Have a list of clients you can contact, to see if they are really legit. (4) Only use Google approved methods, so you never need to worry about getting "busted" and losing your rankings.
(1) Highly competitive single word phrase. (2) 10 two wrods phrases. (3) Bonus for No.1 ranking.
All of which were achieved. I LOVED the small despoit, then no payment till results achieved, and in my case because it was a large amount (10,0000) they let me pay it off over 6 months, which was fine by me because the rankings saved me thousands in adwords so the reality is, if you take into consideration i was able to pay it off with reduced adwords spending, it really cost me nothing
See my comments about him here: http://blog.brush.co.nz/2009/08/site-doublers/
talk soon - Jacqui Jones