Painting works like this. You have a canvas. You have an image, but it's supposed to be on that canvas. So you make it possible for everyone else to see it there too.
The secret to being a great painter is to stay in vigilant communion with the pull of that image. If you can do that, technique falls into place naturally. If you can do that, the painting paints itself. And if that's all you have to do, then the more relaxed and unintentionally you execute your work, the easier the painting process will work for you. You see, if you can stay true to the pull, you have absolutely nothing to worry about. You can't really even make a mistake, because the pull is the truth of the painting, and anything built on truth will have a pure, natural, and imperishable quality to it. In paintings created true to their initial inspiration, "mistakes" become enjoyable. You can still work intensely and be relaxed at the same time – all that matters is the purity of your focus to your image, but especially to its pull.
The pull is whatever it is that draws you to that image. It's not the image itself. Abstract expressionists and experimentalists might believe that they don't have an image, but they still do. (They just have an emotional or conceptual image, but it's still an image, albeit a more abstract one.) By focusing on what attracts you to your image, you concentrate your subjectivity to where it belongs, and the rest of you becomes more objective, which means that you become more in touch with the sense of light, space, vibrancy, or composition in your painting. You're able to maintain the vitality of the image if you can retain the newness of your inspiration. If you focus on the image itself too much, you forget about what it was that drew you to the image in the first place. It can lead you astray, and you get so busy looking at it that you forget to see it. If you get stuck on a problem, you're probably looking in the wrong place.
Why you chose this image doesn't matter. If your audience knows why you chose an image they might appreciate their new understanding of it, but good paintings affect us whether we understand them or not. So quit worrying about it.
People talk about developing their talents, but perhaps it wouldn't be so crazy to say that we uncover or dislodge our talents instead. They're already there from the get-go – you just have to learn how to get in touch with them. If you could ever paint a great painting, you can do it right now as long as you can listen to the pull, and are in touch with your talent. If you're not in touch with your talent, you just haven't worked enough yet, that's all. All great painters have only one thing in common: they worked their asses off. If they didn't paint many paintings, it's not because they weren't working. You can still paint while you're not painting, if you nourish pull in your heart.
Buy stretchers. Stretch canvas on them. Gesso it. "Pop" the corners with corner wedges. Buy oil paints, medium, and thinner. Buy brushes and palette knives (I use trowel-shaped ones). I trim a lot of brushes with sharp scissors (not the tips). Always have new brushes around so that you're not precious with them.
You can draw on the canvas with a pencil and (sort of) wipe it off with thinner if you want. You can paint underpaintings with very thinned-out paint if you're into that. (I paint on a black background these days.) Buy a thick sheet of glass, paint it white underneath, duct-tape the edges for protection, and you've got the only palette you'll ever need. You can clean it with a scraper.
You don't paint with colors, you paint with pigments. You don't mix colors, you mix pigments. Some are opaque, some are transparent – pay attention to that. Once you learn your pigments, colors will still be problems but they'll be fun. Colors are three dimensional: they move side to side between primary colors, up and down between black and white, and in and out depending on their saturation and the thickness of application. You can use the paint straight from the tube (there's no law against it), but keep in mind that you're driving in slow gear. Are you climbing a mountain? Perhaps. But medium and thinner are the gears that can get you out there on the open road. They thin out the color, though, so balance is key. Oil dries slowly. Thinner does not. Paint that contains a lot of oil is called "wet", paint that contains a lot of thinner or less oil is called "dry". If you add too much thinner, the paint may want to bleed. If you add too much oil, it may be difficult to paint other layers on top of it once it's dried. If you use the paint thickly and it has a lot of medium and thinner, it will wrinkle when it dries. If you splash thinner or thinned paint on a thin layer of slightly oilier paint, it will push it away.
Oils dry from the surface inwards. When painting in layers, you should always remember that if you paint a "dry" layer on a "wet" layer – assuming the wet layer isn't completely dry – then there's a good chance that your painting will crack. Always work dry to wet. Wet on top.
I usually varnish my paintings, although it's no longer fashionable. I routinely let my paintings dry for at least a year before I varnish them, and may wait longer for super-thick paintings. I like varnish because it brings out the blacks and the depth of my work, and because it's an added layer of protection.
Restorationists can remove varnish. It changes the colors and can affect fine details, but you can learn to work with it and love it. When painting, step away from the painting often. Paintings have three levels: distance, comfortable, and detail. (If you're a beginner painting a landscape, there's a related classic trick you can use. Give the landscape three layers of distance: one close, one far away, and one in-between. Make one layer dark, one light, and one medium.) If you stay in vigilant communion with the pull every you time you use your brush, you'll do a good job. Don't worry if you **** up. If I might paraphrase Don Van Vilet: "What I like about painting is that if you don't like something you can just paint over it."
Every time you're done for the day, clean your brushes first with thinner and then wash them against your palm under a faucet with a mild soap, preferably 100% olive oil. Never let a brush lean or stand on its tip. Traditionally you use your mouth to shape fine brushes for drying, but since you're painting with a lot of poison I can't recommend that. Clean your hands well with soap. Don't leave thinner or rags where they can catch fire.
97% of the time a painting looks better framed, and it will be more easy to sell, too. Most people who claim otherwise are lying to themselves to save effort and money.Every single time you begin a new painting, remind yourself that there are no rules or restrictions, that this is a place of complete freedom. The excitement of painting is constantly managing a series of accidents, directing them into a luscious whole. It's the joy of the artistic flow, the puzzles, and the unexpected delights. You have to stick with it, though – tenacity pays off. You know if it's not done yet, so don't lie to yourself. Are you seeing it with open eyes? Are you distracted by problems instead of seeing relationships?
Clumsy hands can still produce spectacular paintings, but clumsy eyes produce lifeless paintings. Painting is learning how to see without looking, and how to focus from the back of your mind instead of the front. (Figure drawing is the best way to learn how to see spacial relationships.)
If you're painting for the first time, buy way more paint then you need and try to use it up as fast as you can. Get to know your materials. Be loose, experiment, and have fun. Keep moving – don't snag on trifles. Each new canvas is an open universe. No one else has access to your visions; only you can paint your paintings. So keep at it.
This is all you need to know to become a great painter. You'll figure out the rest. When we communicate our inner visions non-linguistically, through things like art or music, our communication breaks through cultural, social, and class barriers, which are all regulated by language. That's why prehistoric cave paintings are still beautiful to us, even after many millennia.
A beautiful painting doesn't capture a moment in time, a beautiful painting is a timeless moment.