It is possible that those techniques aren't working for you. It's also possible that something else is going on. We need to dig into the data a bit more deeply to figure out what's happening.
Use the below article to analyze the verbal portions of your test (and the quant, too, if you want!):
http://www.manhattangmat.com/blog/index ... ice-tests/Figure out what the differences are, first - did you drop in everything? Did you only drop on certain question types? Did you have any timing problems in certain areas?
Then dig in even deeper by looking at individual questions. Let's say that, on the first test, you did really well with Critical Reasoning Find the Assumption and Draw a Conclusion questions, but your performance dropped on the later tests. Go look at the questions themselves. Why did you get the later questions wrong? When you look at them now, do you think, "Oh, I know how to do that! I can't believe I picked C!"? That would indicate a careless error of some kind. That could be caused by using a technique that you don't really like, and so it messes you up, but it could also be caused by timing problems, fatigue, lack of concentration...
Or do you read the question and think - no, I really didn't know what to do (and maybe I'm still not 100% sure why I'm wrong or why the right answer is right). That would indicate some kind of content or process problems, and that is probably not tied to how you're taking notes.
Anyway, so go dig into that data and then come back and tell us what you found out.