I recall seeing a brilliant book title: "Life is Goodbye, Life is Hello"...and I thought, I don't even have to read that book.... the title is haiku enough.
I like painting over old paintings for the "Hello-Goodbye" aspects of it. (Steps below)
Painting: Celeste Bergin, Homestead (painted over "life model"), oil on 16x20 stretched canvas
1. Place the darkest darks directly over the old painting
2. Next, place the lightest lights (I used a palette knife)
3. Block in the other major shapes and approximate local colors
4. Add the sky (now the entire canvas is covered)
5. Strengthen the buildings and place final details ....finished!