I have plotted alone too much. When there is no one to bounce the ideas off of, no one else to poke at the notion with their sticks, then my options are limited. I write on my white board, I pace, and I talk out loud. I can get it done, but the result will not shine as bright.
Suddenly, that world comes into greater focus in my own eyes. The addition of their thoughts is, in part, a validation of my own which gives me confidence to move forward, and the other part is fuel on the idea spark I started with. Before much time has passed, there is a bright flame.
It is important (to me) at this point to keep feeding that fire. To hammer out some details, to consider the tropes, the stereotypes and the current trends, and then to take a hard look at this idea before me and identify what is 'normal' and certain to be anticipated. I follow that up by actively asking myself what emotional appeal can be found in altering the plot or characters to avoid that ground which has already been explored.
You wouldn't dig for gold in an old mine, right? You and I both know that endeavor would most likely be a complete waste of time and effort.
Then...because that spark has become a blaze, my passion is burning bright for the project, and the momentum has built and is hurlting me onward...there's no stopping me.