Create an Unique Painting from an Idea | Alexandra Novik-Khamis

How do you take the beginnings of an idea for a painting and develop it into a finished painting? There are three steps: research, development, and execution. 
Artists call it CSI for Art: Concept, Scheme, Innovate.

Concept: The initial idea you have for a painting, or something you see has that's inspiring or you'd like to try, that's the concept. You do some research and investigation on this idea, to see what else you might discover, whether it's about a particular artist or paintings by different artists on a similar subject or in a similar style.

Scheme: Figuring out what you might do with the concept. The aim is to consider options and alternatives, develop and refine your idea(s), try out a few through thumbnails, sketches and/or painting studies.

Innovate: Mix what you now know with your creativity and usual artistic style, to come up with something that's yours as you create your full-size painting.

Opening up a brand new canvas is exciting to me, but it wasn’t always that way. Before I got into the practice of painting regularly, I sometimes found facing a blank canvas rather intimidating. I’ve talked to several beginners and part-time artists who feel the same way. They want to paint, but they’re not sure of their subject. If you find yourself in this metaphorical boat, I have some painting ideas you might find useful.
An idea for a painting, a Concept, can come from anywhere and everywhere. It might be something you see outside, a painting in a gallery or one a friend's done, a photo in a magazine or on the web, a line of poetry or from a song. It can be a vague idea or a definite idea. It doesn't matter what it is; what matters is that you take the concept and develop it.

If you're short of time, still take five minutes to jot down the idea in your painting sketchbook or creativity journal. Do it immediately, while you remember. Then it's saved for a day you may need to break a creative block or wish to try something new. If you use a sketchbook to investigate an idea, you've got all your bits and pieces in one place. It's then easy to sit and look through it all. Another option is to put everything into a file, to keep it all together.

The first thing to include is the initial concept, the thing that caught your interest. Make notes about what you like about it, then dissect it by taking each of the elements of art in turn. Some you'll probably look at more in-depth than others. I know I tend to focus mostly on composition and color.

Once you've researched and investigated your concept, it's time to Scheme, to develop and plan. Think of your sketchbook as a sketchbook, notebook, diary, photo album, all-in-one. There's no right or wrong way to record the information and ideas you're gathering and developing, do it however you like but be sure to do it. Take a look at this photo of pages from a notebook of Leonardo da Vinci's notebook and you'll see how the pages are full of written notes. Sometimes that's faster or more helpful than creating an image.

The point of a study isn't to create the perfect still life painting, but to try out an idea without investing too much time or paint. You can then easily compare and analyze, make notes of what you like or don't, and benefit from further ideas that painting the studies generates.

You'll get to a stage when your fingers itch to paint an idea at full size. This is the stage to Innovate, to mix your creativity with your idea and research to produce a painting that's your own. Choose one of your options from your sketchbook, decide on the colors you're going to use, the style of brushwork, the format, and so on. Make a note of this in your sketchbook, then get painting.

Don't artificially constrain yourself by thinking "Oh, I could never do that". It may be you're attempting something at the limits of your present painting skill, but by doing it you'll be building on those skills. You may not get the result you wish, but you'll definitely learn something by trying. Keep the painting and a year from now try again, then compare the results. You'll probably be pleasantly surprised at the improvement.

Some information is taken from here