I remember when I was an art student, very young and thinking that paint it was just apply oil paint onto the canvas, that is it, I learned to paint, but no to planned, it took me more time to learn to observe, not just a superficial look but learn to see carefully and planned how to start a painting.
And here is my observation process after so many years painting.
First I pay attention to the contrast, where the dark areas are the most intense and where the lightest ones, and the proportion of the space occupied by each of these zones, I will know that I will have to use more dark or light colors in my palette, if they are very dark I will take into consideration not to use too much white and get milky colors and if they are mostly light colors, I will take into account not to dirty them.
Second, I identify the strength and purity of the colors as well as the gray colors, so I can choose the colors I use in my palette, I have a range of 25 to 30 colors, I have three tones of yellow, 5 tones of red, 4 Tones of blue, 4 tones of green, 3 tones of orange, 4 tones of violet, etc. Then I can not put all of them on my palette, if I would, surely I will not touch all of them, then I choose the colors according to the model that I have in front of me.
Third, I see the contrast of light and shadow paying but now paying attention to the temperature of the colors, I can see if the light is warm or cool, if the contrast is quite intense or low, I analyze the warm, cool and neutral colors wich are the most difficult to distinguish, so I take special care in the blends of these neutral colors, mostly are grays
For any subject you are going to paint I advise you to follow this analysis, it is easier to have something planned than to start without any order, if you have your own order and you would to share with me, please leave a comment below, I really apreciate.