Colors and markings are important. Don't get me wrong with that point. One thing I look at is size. I'm not talking about a older snake that is sub adult and larger. I'm talking about juveniles. I like to see a snake that is well fed. A lot of breeders (and pet shops) will feed the minimum and I understand keeping cost down. I'm not saying I would not buy a snake from them, but when I see a young snake of a good size I would pick it over the ......smaller one. I just like the assurance that it's a good eater!