Help with design

I was wondering if someone could help me. Currently I am working on my own models and re-textures for my own datapack and wanted to add a bloody design to textures.
My textures are mainly black coated with blood spats. I really struggle to give it the feeling it has blood on it.
Anyone have some nice advice on consistently replicate a bloody design on textures?
Maybe a large transparent palette that i can overlay and move around on my textures? Idk how others do it.