Drawing light instead of drawing shadows
Like it sounds obvious when you say it out loud but shadow is just lack of light, so a lot of times it's easier for my brain to "draw light" by erasing shadows in my multiply layer instead of like "shading"
This scene in Invader Zim was supposed to have traffic on the road but the animators accidentally left them out. The audio for the traffic is still in the scene, and Zim and Dib still act as if there is traffic between them