Identifying an unmet need, getting a market fit for a solution, understanding what people are willing to pay are all counter-intuitive for engineers, but essential to make money.
These are my recommendations to anyone who's here and not getting the traction they want, or are considering starting a business. The 1-Page Marketing Plan - Alan Dibb. The Right It - Alberto Savoia. Monetizing Innovation - Georg Tacke & Madhavan Ramanujam. Obviously Awesome - April Dunford