Well, at first I just try them all right away. How could I resist?
I'd then come back later to give it a full-wearing or several trials on either side of the arm before reaching a conclusion whether or not I like it and if it deserves a few more tries. I am liberal with the amount I apply, so I REALLY prefer samples of at least 2ml. I don't take notes since I remember most of the things I've smelled. If my memory gets rusty, I just reach for my sample.