One of the hardest parts in NaNo is encountering scenes you just do not know how to proceed. The answer to those scenes is to just write the scene and don't look back. Yeah, more than likely it is not going to turn out to be the best you can do, or be what you want, or even look pretty, but that's okay. Wing it, make it up as you go, just write and see what happens, throw a hobgoblin in the room and see what your characters do. The purpose of NaNo is to reach your goal of 50,000 words.
Remember, November is when we throw all the ideas at the wall and December is when we edit and see what sticks.

NaNoWriMo's About Page wrote:
Because of the limited writing window, the ONLY thing that matters in NaNoWriMo is output. It’s all about quantity, not quality. This approach forces you to lower your expectations, take risks, and write on the fly.