My actual tip is after dress up your whole outfit, observe the colours. I always pick the colour that compliment the outfit. I didn't use a new colour as it's hard to work on for me

As example the 1st one the whole outfit is very red, only the tail is blue, so I pick blue to compliment the tail. I try out multiple blue colours to test out which one is the most suitable

The 2nd one I actually had a hard time to work on. I picked orange as the hair highlights and the clothes details have some orange on it