I try to challenge my understanding of color by not color picking from the photos I'm referencing. With this one though I decided to first explore the photo's pallet with the color picker window open, just to try and see how it was all working together instead of just guessing. After I studied the image like that I went about painting from what I'd learned but still without color picking for the actual study painting. I found this to be a great way to commit to memory what I was discovering while exploring the photo with the color picker. I'd highly recommend trying it for yourself if you already haven't!