Try to forget what objects you have before you a tree, a house, a field, or whatever. Merely think, 'Here is a little square of blue, here an oblong of pink, here a streak of yellow,' and paint it just as it looks to you, the exact color and shape, until it gives you your own impression of the scene before you.
I keep a hotel room in my town, although I have a large house. And I go there at about 5:30 in the morning, and I start working. And I don't allow anybody to come in that room. I work on yellow pads and with ballpoint pens. I keep a Bible, a thesaurus, a dictionary, and a bottle of sherry. I stay there until midday.