Here is my initial layout of the painting.
You can see that I start the painting by sketching the elements in, checking to make sure it all fits the way I want on the canvas and that it looks good and is balanced. I also check the perspective before getting too far in the painting because that is hard to change later. Then I start adding color and detail to the painting. Click here to see a picture of the objects that are part of this marine themed still life painting.