No picture again tonight. I am on a primitive borrowed computer and it won't agree to do that. Tonight's idea is to make haste, slowly. One way to do that is to keep the paint transparent until you are as far into the painting as possible. That is.....stay out of your white.As long as you are working transparently you can shove your "start" around all you want. The instant you add white to the painting it is locked down. It is far harder to make an alteration. Building up too much paint early in the process makes things harder. It is easier to manipulate thinner paint layers.
When we are laying in a picture on a white canvas we are generally delineating the darks and leaving the white of the canvas behind for the lights in the earliest stages of the drawing. Mostly you start out by placing your shadows, they are what is usually darkest before you in nature. Keeping these shadows transparent often looks better than having them opaque. Your may load lights with white, but it is usually good to keep your shadows thinly painted if you can.
Another way to more gradually "find" your painting on the canvas is to keep your picture "soft" in that transparent color. . Until you really know what is happening all over the canvas it is best to keep the painting fuzzy, like an underexposed photo. Opaque paint is far more likely to give you hard edges Also, if you go too hard on your edges before you are really sure of your drawing, you will respect those lines out of relationship to their real accuracy. If you keep things fuzzy for a while you will be more likely to willingly correct a shape that is off. Both this and the transparent paint suggestion are alike. They are ways of withholding too much commitment earlier in the painting process. It is best to add commitment later rather than too soon. This will help you avoid careful finishing one part of a painting and then discovering that passage is in the wrong place ever so slightly. If the passage is just ghosted in you will happily move it. If you have worked it up already you will be tempted to leave it wrong.
EVERYTHING IN A PAINTING NEEDS TO BE RIGHT. ONE UNCOMFORTABLE PASSAGE RUINS THE WHOLE PAINTING. A PAINTING IS ONLY AS STRONG AS ITS WEAKEST LINK. IF A SINGLE PASSAGE IRRITATES THE VIEWER, HE WILL REJECT THE ENTIRE PAINTING.
An orderly and careful approach to a layin will save time correcting problems later. It is easier to not make the mistakes in the first place tan to correct two or three interlocking mistakes in a half finished painting later.