Need advice on "composition"

I've got a full sleeve minus inner bicep and ive got an angel, knight and woman and a princess. I'm working on a patchwork tattoo sleeve and the designs I'd want to get tattooed either look too similar or are the same things. I don't think it's right to have 7 angels or 4 different snakes and stuff like that. Is there any sort of advice to be given on this other than "look at other designs"?