How can you determine an SEO developers skill and success rate?

Word of mouth is usually how good SEO people get business, ironically.

You definately want to see other projects they have worked on and what the results were. It would be nice to have some contact with the owners of the previous sites so you can verify good results.

Beyond that learn a bit about SEO yourself, and ask them what they will be doing, if it sounds like you know more than them....don't hire them.

Do not anyhow pay money to them unless they show you proof of SEO in live.

Ask them for a specific step by step plan of action. Make them put deadlines on things.

"This task will be done on XXX day."

Lot's of frauds out there. I'm assuming you have stiff competition?

It's very simply just check out their previous projects success.

$500 and $1000 a month sounds a lot to pay to a new provider. For how many sites and keywords was this?

As for the guidelines: whichever provider you choose - start small.
These days you can find SEO providers charging under $100/mo and a lot charging $100--200/mo. Pick up one and test them - give them 1-2 sites for a couple of months first and see what results they can get you. If good - give them more. If not - then move on.

But before you even make the choice - talk to them, ask questions - see how fast and how well they reply. Willingness to communicate, qucikness of response and good customer support are crucial when selecting service provider.

'Do not anyhow pay money to them unless they show you proof of SEO in live."

Very bad idea. No good one would ever go for this.

"The last one we hired is from the U.S., paying them $1,000 a month ... we hardly got any improvement. They were a reputable company, part of the Inc 500 fastest growing companies."

Hehehe... this tells me that likely there is something wrong with... YOU! Maybe you give $1000 where you need to spend $10k if you get my point. Refine your project, make it more narrow focused in order to see results. It seems like you are in a highly competitive market. You have to play to your league.

If you want to hire effectively hire 1 or 2 SEO consultants from oDesk (possibly $30/h or more) to help you interview potential SEO providers. This way you won't have to do lots of studying yourself.

P.S. be sure to let enough time for your SEO to show its results, especially if your domain(s) are relatively young. Your SEO'ers might not be able to do anything that can give further results before your domain ages enough. If you stop though you will never get these nice future results.

I can't imagine hiring anyone from the PI.

Have you thought about paid advertising?

If you have a real business....

SEO is a game that comes with no guarantees. Obviously, you
are looking for that. It might not even be possible. You have
competition, and some of it is in concrete, steadfast.

In fact, after a so-called reputable company after 6 months showed
little improvement, I'd be thinking...paid advertising...but only
if I actually had a real business. You've paid $8000+ on
"seo." It's time to refocus your dollars.

Paul

Hi,

Take my words , do not hire anybody, learn seo by yourself ,there are lots of useful stuff on the net and try to follow some people who have made success with there website and follow there tips.

Like you ,i have also spent 1000 of $ but no use, After that i have started doing it by myself , now i have lots of keyword ranked on the 1 page of Google, well my blog also got hit by panda, that is also my mistake , Lots of article from my blog get copied to other website because of that ,my blog blog hit, Now i am working on this , hope to get atleast 50-60% traffic back after next panda update, waiting eagerly for it..

Regards
Shan

First be willing to invest in making mistakes with different services eventually you will naturally develop a filter for BS.
I know no one else can tell you exactly how to determine whether or not you should trust the service exactly, and I believe the best resource that you have is your gut feeling.

Being the founder of topiaservies that delivers first page rankings to client, which is an extremely rare thing when you take into consideration, there are only 10 spots in the first page of Google and we have got every client that has worked with us to the first page so for.

Some of my prospective clients are uncomfortable with their belief in our provided service, which is absolutely understandable yet I would never accept any client that begins our service with such a negative feeling.

However, keep in mind; there's a difference between the negative gut feeling and a natural fear of the unknown. Only invest what you're willing to lose and don't be afraid of failing.