Our web site is indexed by Google but completely invisible in the rankings. We have checked everything we could think of, used webmaster tools, Xenu, etc. We have corrected some issues and asked for reconsideration 4 times in two years (in case we had a penalty). We have yet to see an improvement. The bottom line is that we have exhausted our own resources and need professional help.
The problem is that we are not sure how to go about selecting a reliable, serious SEO company. We don't want outlandish "page one guarantees" promises : we just want good expertise.
If anyone cares to comment on that we'd love to get some reactions !
Search for SEO companies that have client in the same industry as you are. Avoid SEOs that: claim they can get you first in every keyword, use methods that are against the Google's guidelines, have recently been banned etc.