This has been a tip before, but it bears repeating.
Sometimes in our haste to gather information, we fail to record why we did certain things and what led us to certain conclusions. Our reasoning may have been correct, or maybe not. If you don't write down what you were thinking and your reasons as you do it, duplication of research is impossible and sooner or later you will wonder why you did what you did or someone else will ask how you arrived at that conclusion.
Writing in my research notes why I did what I did as I did it reduces the chance I make mistakes along the way. It also makes it easier to review my thought process later and see how I was wrong---or how I was correct.