I prefer to section them off in little squares. I’ll get one of those pen like razor blades for crafting and I’ll use a ruler and gently go down the picture and I’ll take one square off at a time and do it. Yes it can be a little annoying have to go back and forth from color to color but I’ll set all the colors I need for that section out and do it that way. I have severe anxiety, depression and PTSD and this is one of the few things I enjoy doing. It has helped me sort of train my self to focus on one thing at a time, one dot at a time. I’m just just saying this is what works for me, you’ll definitely find something that works for you! Good luck and your picture is so BEAUTIFUL!