The first thing to do is determine what you would like to do with the new software. You should be able to describe it in under 100 words- capture the essence of your requirements and ignore the detail. Some examples are:

Manufacturing Planning System (in 30 words)
We want to be able to convert orders held within our Epsilon accounts system into manufacturing schedules. We would like to be able to run the reports whenever we like.

Computer Security System (in 44 words)
We want to allow our users to access only specific programs on their PC's, and to lock them out of programs that they are not entitled to use. We would like to be able to record and report on when people use which programs.

Contact Management System (in 51 words)
I would like to be able to keep track of the people that are known to my company, to be able to record information about them (eg address and telephone) and contact notes. I would like to be able to share information over the internet to sales personnel in other locations.