Aaaa I just think of a random theme/item and several things that could sorta be related to it! [ ex : Sea > Seashore > Sea Shells > Crabs use shells and collect them = A Humanoid Crab  / Seashell collector ] As for colors I choose them according to the theme :>  [ ex: Teal, Blues (sea), Cream colors (shells), Red (crabs) ] 

Hope that makes sense 😭😭 my thought process is so complicated,, and I'm very happy you like my designs !! It MEANS SO MUUUUCH 💜💜💜💜