Thin coat of paint?

 I keep telling people... "only use a thin coat of paint."  What does that mean?

If you can still see the background through what you just painted  that's about right!

This is about right.

After the second coat you may still see the white background. That's not bad.  Thick paint is more likely to peal off when you are removing the tape.  Paint builds up along the edges of the tape.

Paint Ridge.

That creates a ridge... It can easily be removed with sanding, but that complicates your life.

Yellow is the worst to deal with... Takes many coats to cover and peals easily. Thin coats help.