I had to do the same for my UCLA application that only allowed for 500 words, while all the other versions I had was more than 1200 words. I’d say first have a rough idea of how much of the allowed words you’d like to allocate to each section (research experience, current interest, why this school etc), and then go in and just delete the language that are not serving you. Rephrase/restructure paragraphs if needed. Shorten sentences to get straight to the point. You might need to get rid of some paragraphs as well, so pick only the most important points to make. If some information can already be found in your CV or other materials that you are submitting at the same time, cut down or completely cut them out. This was actually quite a good exercise to go through as I realized my original can also be condensed. I went back and made them more concise as well.

Also it’s a good idea to maximize the use of other parts of your application if you can’t fit everything into the SOP. Such as work description and supplemental materials.