Sheesh
Looks like the design part is a very small compared to the rest of the process.
My best thing is just to estimate my blood shed and time and give the rest to a specialized marketting company to save myself the hassle.
A good technical guy is usually bad at marketting. One reason for this is that technical guy has to be honest to make his product work, while marketting guy has to be the opposite to make his product sell! :)
Regards
Mahmood