I started designing my tortoises, coming up with characters with basic shapes but still psychically in form of a tortoises. I've tried different heights and shapes regarding the body. having my tutorial - my tutor liked Number 4, 12 and 19. They look appealing with huge heads and foot, tiny shell which tells that this character would not get far in a race. Also looking at number 15 makes the character quite different and also gives way to a back story on "how did it get stuck in a shoe and why"
As for the faces 3, 9 and 10 looks like the faces for my character as they are cool, cocky and well relaxed.