Google's Matt Cutts Explains Tips on Ranking on Google
"If you're thinking about hiring an SEO, the earlier the better. A great time to hire is when you're considering a site redesign,
or planning to launch a new site. That way, you and your SEO can ensure that your site is designed to be search engine-friendly from the bottom up.
However, a good SEO can also help improve an existing site." - Matt Cutts, Google.
Some useful questions to ask an SEO include:
Can you show me examples of your previous work and share some success stories?
Do you follow the Google Webmaster Guidelines?
Do you offer any online marketing services or advice to complement your organic search business?
What kind of results do you expect to see, and in what timeframe? How do you measure your success?
What's your experience in my industry?
What's your experience in my country/city?
What's your experience developing international sites?
What are your most important SEO techniques?
How long have you been in business?
How can I expect to communicate with you?
Will you share with me all the changes you make to my site, and provide detailed information about your recommendations and the reasoning behind them?
PositionKing observes search engine friendly practices suggested by
each major search engine including Google, Bing, and Yahoo and accepted
search engine optimization industry standards. We are proud of our commitment
to provide quality services.