i would like to know what information you recommend i gather when starting a new contract/project.

i have previously concentrated on developing my own software, however i am getting increasing demand from other (non IT) companies to work on their existing databases and develop software for them. of course i want to look as professional as possible in the first consultation and collect as much useful information as possible without having to ring the next day and say "i forgot to ask you this and that"

your guidance is appreciated.