maybe you're reading too much while you're skimming or writing down too much. I think I do something similar to Kaplan's method. I number the paragraphs and write down one or two key words per paragraph. I usually look at the first and last line, and if any unusual words or if any names catch my eye without actually reading it, I write it down.
Don't try to read it when you're looking for keywords. You're probably doing the thing where you're trying to skim but then you go back to reskim/reread the word and so it's taking too much time. Try to stay relaxed and only look for words. Ignore the sentences until you actually read the questions. This works pretty well for me. I can get through each passage in about 2 minutes of keyword search and then hunt back through for the questions and spend about a minute on each question. And like the other topics, if you can't find something skip it. It's too easy to get caught up in the 'which of these statements is incorrect' questions. That's usually where I lose most of my time.
I hope this helps.