How not to lose a good idea?

How not to lose a good idea?

How much time has passed from the initial idea to its implementation? Most often it is a lot of time, which can be divided into three stages: The emergence of the idea => Design idea as a model => Practical implementation. I propose to focus on the second and third steps. Often a good idea has not leading to implementation is due to a poor study of the main ways for implementation. Losing a good idea or its underestimation can been critical.