First, I'd recommend going through an easy-to-digest version of a basic marketing course like the 5 pages at http://tenonline.org/art/mm1.html
Then I would follow the basics found there... determine what your 'market' (location, community) needs and if you're the expert to deliver on their needs. Sounds like you're already here. Then write down (a Business Plan doesn't need to be overly-fancy and most begin on the cafe napkin or back of the envelope and go from there) what you've got to offer, who you will offer it to, what unmet need it delivers on and any basic parameters of your offering.
It will help if you take off your "Boss/Owner" hat and put on the "Customer" hat to give yourself a look at how the other side will see what you're offering:
- does it offer something I need (or want)?
- does it lack something I need (or want)?
- does it seem to be of decent quality?
- will it be something I can afford?
- will I feel good after I begin to use this or after I pay for it?
- will I be able to refer others to this in good faith?
Then, put your 'Boss' hat back on and ask similar questions so that both parties will be able to look back on the deliverable and be satisfied that neither side got the short end of the stick... (don't promise 'forever' repairs or modifications, for example, but do offer some sort of guarantee of quality deliverable, arbitrated by a qualified third party if necessary, for example)....
Hope this helps, Marketing has been an interest of mine but I hate the potential for manipulation and unethical behavior by those who are more savvy with lower integrity.