What brainstorming what should you do to generate a large number of ideas?

I've never done it but I'd suggest first ensuring everyone in your meeting is inventive, ingenious, enthusiastic, proud of his or her achievements but modest enough to recognise others may see better ways.

Also everyone needs to know and understand both the aim and the usual methods, materials, etc likely to achieve it.

Initiative and lateral thinking ability would be valuable, together with a questioning mind able to rise above bureaucratic negativity like ISO9000 and the "We'e always done it this way" mentality that such systems generate.