A painting approach
There are many valid approaches to painting and with experience you will develop your own specific approach. But if you are just beginning, you may want to try and practice the following approach:
1) First make a regular drawing on the canvas. This drawing can be made with charcoal or graphite pencil, and can be anything from a few lines to a completely detailed drawing of all the forms. This may even include where the lights and the darks are and what colours need to be used. Of course, the best tool is some neutral mixture of thinned paint and a brush. However, this takes some getting used to. If you do use graphite you need to draw very lightly because graphite can bleed through your paint.
The advantage of starting with a drawing is that many important decisions can be made up-front and that everything is in place by the time you finish the drawing. After that, all that is left is painting.
2) In the first painting phase you ought to use fairly thinned-out paint. Focus on the big shapes that you see in your drawing. Don't pay attention to detail. What is important here is that you observe the colours of the shapes correctly and that you maintain the lines of the drawing. Start out with the dark shapes. Then proceed with the brightest coloured shapes (i.e., those that stand out), always making sure the colours stay harmonized. Finally, put in the more subtle colours many of which will be duller.
Again, in this phase hold back on painting details. Maintaining the correct geometry of the large shapes, their exact colour (hue, intensity, and value), and their correct position within the composition is the task at hand. And don't forget to include the background.
At the end of this phase the canvas is usually completely covered with paint, i.e., no white areas are left unpainted. This gives you a good idea of how all the colours look like relative to each other and if they harmonize without the influence of bright white areas.
3) In the Shaping Phase you can begin to paint the large shapes and refine them so they start to resemble the actual objects you are trying to paint. In this phase you ought to use a thicker paint than in the Block-in Phase and also a somewhat smaller brush. Also, refine the colour relationships in terms of hue, intensity, and value as best as you can.
This phase usually requires the most time and effort. Still, do not be tempted to put in fine detail. At the end of this phase you should already have a very good idea of how the final painting will look like.
4) The Detail Phase - In this last phase you ought to include details like small twigs, pupils and irises for the eyes, small lines and curves, and highlight, in other words, anything that cannot be done with a large brush. Some details require thin paint (best done over a dry underground) and others, such as highlights, often require lots of thick paint right out of the tube.
All the above guidelines are admittedly not complete in detail but are a good starting point for any beginning oil painter
