"I'll try and make some time for it today."
"Today was slammed."
"I just don't have time this weekend."
Above are just a few examples of the infinite excuses that circle screenwriters like a shark. They mean nothing. They are false. You make your own time. It's not going to be at the same time everyday. It won't be for the length you always want it. It will be during the times you carve out. The you is the biggest part of the equation.
Now, what about that whole creative juices thing? Yes, there are always times we feel the lightning bolt strike and we can bang out ten clean pages. These times tend to be rare though. Make yourself write. Make yourself punch keys for five to ten minutes. Get it out. Then…edit. You will find that the real creative juice and coherency of your story come through in the second and third rounds of editing.
Now stop reading this and start typing.