hello! I saw your post on the forums but I couldn't remember where the thread was ;;
^different ways of colouring pastel colours
1) you could just use a colour that's a biiit darker if you want a subtle look. usually the shade colour is towards the purples while highlights are towards the yellows.
2) using a darker colour to shade (still towards the purples)
3) use more varied colours to shade. e.g. using periwinkle to shade pink, or using purple to shade the pastel blue ^^ just experiment. Also if the environment is a bit cold, maybe use more blues and purples, if the environment is warm, use more reds and oranges.
hope this helps a little! good luck! (: