In my own experience developing a new kind of system from the ground up, I can only say that you have to talk to yourself, but as an extended conversation over a good number of years (a decade in my case). It is essential to occasionally stop working on the thing altogether, and clear your mind of all thoughts relating to it (if possible). If your system is truly compelling enough, it will call you back from out of the depths of your subconsciousness. Then you can see it afresh and be able to evaluate it as it truly is.