"As for the actual writing process...this may not be helpful at all, but my only creative process is to just sit and think, think, think. :) Melodies and chords come pretty darn easily to me, so generating them takes very little time and they tend to finish themselves quite quickly. I don't even need to be near an instrument when that happens; it all sort of takes place in my head." ~Mary Bichner
Get away from your instrument (keyboards, pencils, paper, etc.) and utilize your creative mind to analyze and re-realize your composition.
At any point in the writing process.
I find this most helpful after I've just read a complete early draft in order to avoid minor adjustments to language & punctuation and instead focus on the much larger picture, solving problems as I recall them from my reading.
Mary Bichner is a Philadelphia composer and performer. She has the skill perfect pitch as well as the rare neurological condition synesthesia. Basically, she perceives colors when she hears musical notes. As one article notes "'Perfect pitch' sorta means you can see the code, Matrix-style." Now she works with Arts in Motion as a composer working with at risk youth. She also records music under the name Box Five and recently released the album Leave the Earth Behind. She specializes in what she calls "classipop," which is Brit-rock hooks in Mozart-inspired chord progressions.
Tunes often get stuck in your head. They appear suddenly and stick until they mysteriously leave. You can walk out of the house humming a tune and keep humming it all the way down the street. Plays don't tend to stick like that very often and certainly not in the same way. Mary's advice from above makes sense in the context of music. Hum a tune and keep humming past it (create more, refine, etc.) but how could this apply to playwriting? Playwrights often get lost in words and lost at a keyboard. This is especially true of us inclined towards the romantic process: creation and innovation happen at the keyboard or with pen in hand (not in our creative minds or in outlines). This exercise forces you out of writing and into thinking.
NOTE: In order to stimulate your thoughts I've borrowed the SWOT analysis strategic planning method from the business world. Feel free to replace this with something else. It was chosen because it is fairly straight forward and useful.
At this point you should have finished a (perhaps quite long) period of thinking about your play. Hopefully this thinking was fruitful and produced another draft of your script with improvements and progression. Hopefully this was a restful (instead of stressful) time with your play. Removing your instrument of writing and simply thinking can produce results that would likely not have occurred pen-in-hand. Hopefully they were positive. Press on.