When you focused too much is easily to stuck. Like artrush73 said you need a break. Take a day off in nature.
Of course get with you laptop or notbook. Becouse when you relaxing muse coming back. This is my personnally experience.
Good luck!
A book doesn't have to be written in order. Sometimes, it good to jump to a later event in the novel and write that part while you trying to figure out what to do with the earlier chapter. I think that you force your way through in a linear fashion you often sound forced, which is not good.Jael.
What I do and is working for me, is I usually write when I am inspired. I tried to write every day, but this technique does not work for me. I usually write phrases to be used in the future, but when I am inspired, I write a story from be beginning to the end.
I do not worry about grammar or how well constructed the sentences ar. I write and write until I reach the end. Then the cleaning of the writing takes place days later.
You have to find the technique that works best for you. If you are stuck, leave it alone. Inspiration will come at the right time.
Sometimes I start writing about a particular topic, I get stuck like you. I move to another story, and I come back to my previous writing when I am relaxed. Sometimes, I write without thinkning or worring about anything.
This has helped me to find inspiration deep inside of me. Always write taking in consideration how would you approach a particular situation/issue. This also will help you focus more.
Write the beginning and the end. The in between will come along the way.
The easy way to go is to take some supplements for concentration, check it out here hubpages.com/hub/Supplements-to-Gain-Brain- the supplements will help you be more concentrated, it would be much easier to get into writing mode, you would feel refreshed and full of energy and in full control. The brain is like a muscle, when you over think, or over concentrate the brain gets "overheat". Take some time off, take 15 minute brakes.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.