As you are writing, skip all the words that are less than 4 letters long. No need to skip them in your thinking, just don’t write them down.
Pause partway down the page to give your mind a rest. Read over what you have written. Scribble out any short words that might have slipped in. Try reading it aloud. Then continue writing.
Illustrate your work if you like. Give it a title. Sign and date it, too.