This is more about observing and capturing a thought or a moment, than impressing yourself.
I like to use a cheap unruled notebook. The cheaper the better.
I steer clear of moleskin and the like, It'll only make me care too much.
Interestingly, I also find it stops me hoarding. If I have a record of something, I don't necessarily need to keep hold of it.
“Observe, record, tabulate, communicate. Use your five senses. . . . Learn to see, learn to hear, learn to feel, learn to smell, and know that by practice alone you can become expert.”
William Osler (1849-1919 Physician, described as the Father of Modern Medicine, pathologist, educator, historian and author)