Start bulding a prototype...

The first thing about  a venture is the product or service...so start building them with all the resources pooled to gether and make it worthwhile. 

There should a minimum design spec for a product a working model and more importantly same is required for a service firm also. 

All the marketing and other ideas can wait, because you need to be sure the thing works well and test run that to enhance design and operational utility or service offering. That keeps the R&D period long enough to help you tide later embarrasment.

Think it up... and if you are technology entrepreneur, then you have to be ahead of the  rest....

signing off

TFE