It's been a while since I've done lineless, but if it helps, don't delete the sketch until you're absolutely done with the picture; I usually keep the sketch around until the end because it helps me distinguish between objects in a picture!
This really only applies if you're trying to do fancier shading I usually shade the picture quickly and then do more detailed shading later; it helps me with details!
These are just my two cents so don't feel like you need to follow them though!