One of the most powerful tools is the unconscious creativity.
This is when I simply allow my unconscious to do all the heavy lifting for me creatively. It is the use of this method that has allowed me to write quickly when working or doing any other scheduled work.
This method falls back on the old advice to “sleep on a problem”.

Have you ever been worried about a decision or struggled to remember something important before bedtime only to wake up the next morning with the answer sharp and clear in your mind as if it was a gift from the gods? It is a gift of sort, but no outside agency delivered it to you. The answer reached to you by your greatest creative by ”your subconscious”.
Unconscious creativity uses the power of the unconscious mind. Often a solution will pop into your mind unbidden, as your mind continues to work on the problem below your level of awareness.

The human brain is a beautiful, highly-functional instrument and yet we utilize so little of its power.
Our unconscious does amazing things for us. It helps with our daily coordination needed for useful tasks such as walking, eating, breathing, driving. It stores memories for us, it keeps a check on those things that are truly important to us , it reminds us what we believe. Most of the time it does these things without us even having to consciously think about it – that’s why it’s called the unconscious !
Using the unconscious as a creative tool is very simple.
Spend some time consciously thinking about your writing task or challenge. What are the parameters of the project? What are the special requirements? What ideas do you have already? What specific questions do you need to work on further? Sometimes even spending some time jotting down the ideas you have is a good idea. Don’t work on shaping or organizing them. Just record them on paper or computer file.

You may not even need them later, but the process of recording them can be a helpful way to prepare your subconscious for its task.
Then forget about it! That’s right. Move on with your life and consciously think about something else. Revise another project. Read something for education or pleasure.
The incubation time varies according to your creative personality and of course the size of the project at hand. I’ve found a few days usually works best although even giving myself a few hours can be beneficial. Doing something physical is often helpful during the incubation period and sometimes this is the only time I really get my personal housework accomplished!
I have heard of several authors who are able to program their dreams so they are literally writing in their sleep. Dreams can be as vivid as a painting, as resonant as music, and as symbolic as poetry. Using this method I can often write a scene a day (sometimes in less than an hour) which is fairly decent progress while simultaneously working full-time and maintaining a life.
While it is often frightening to think about trusting something as important as the writing project of your heart to your subconscious, it might help to remember that your brain is a muscle of sorts. Your unconscious mind controls many muscle functions for you all the time – try thinking about the way that you walk while you actually walk.
The body and unconscious mind handle all the details. Thinking too hard can actually interfere with the zone and this is true of writing as well.
So give unconscious creativity a try and see how far it takes you. Simply program your subconscious and then leave it alone to incubate for a while. It may take some time to find the method of tapping into your subconscious after your incubation period.

Best of luck with your writing!