There are a myriad of ways in which a project can go off track, so in order to get the right service for you we’ve enclosed the detailed American Translators’ Association (ATA) guide entitled Choosing The Right Translation Service – How to get it right! It’s packed full of easy to find information that should answer many of the questions you may have.
http://www.atanet.org/docs/Getting_it_right.pdf
It can be downloaded in a number of languages so just click on the link pertaining to your native tongue.