Get in touch with real potential users
Many projects fail (and startup companies go bankrupt) because they
develop a system for which nobody has any use.
Even though the system may be user-friendly,
it is important that it serves to perform tasks which need to be
performed by real people.
Never believe yourself when you think the system will be good for many
people because you believe it will be good for you.
Sometimes you may be able to find real users but they consider their time
to be too valuable to collaborate in the development of the new system.
A bribe (t-shirt, mug, ...) may work better than a professional reward.
If you can't find them, who is actually going to use (and buy) your system?