Thomas
To add to what Howard wrote - you need to do the fundamental research for your business idea; even a paid consultant will need basic information from you - such as:
Who wants this product or service?
Why will they want it?
Where are they getting it now?
How much will they pay?
How much are your internal costs?
Who are the competitors?
How will you market this product/service?
Why do you think you are going to be a solid business person?
What team of people do you need? Finance? Marketing/ Sales? Distribution?
and so on ........... much much more.
A good place to start is www.bplans.com where you can see sample plans done by the pros. See the level fo detail you need to know.
If you wish SCORE's help go to www.score.org and use the FIND SCORE option to locate your local office. Then fill out their request for counseling form.
Good luck
Alice, SCORE Pittsburgh
edit