The best thing that you can do is to study good examples and try to appreciate, not only their beauty, but how and why they are beautiful. Cultivate your taste in that direction; and with the taste to like good and dislike bad composition will come the feeling which tells you when it is good and when it is bad, and this feeling you can apply to your own work, and by experiment you will gain knowledge and skill.
Rules are not possible simply because they are limitations, and the true composer will always overstep a limitation of that kind, and with a successful result.
Principles of composition, too, must be variously adapted, according to the kind of picture you have in hand. The principles are the same, of course; but as the materials differ in a figure painting and a landscape, for instance, you must apply them to meet that difference.
Suggestions.—The first suggestion that might be made as a help to the study of composition is to consider your picture as a whole always. No matter how many figures, no matter how many groups, they must all be considered as parts of a whole, which must have no effect of being too much broken up.
If the figures are scattered, they must be scattered in such a way that they suggest a logical connection between them as individuals in each group, and groups in a whole. There should usually be a main mass, and the others subsidiary masses. There should be a centre of interest of some sort, whether it be a color, a mass, or a thing; and this centre should be the point to which all the other parts balance.
Simplicity is a good word to have in mind. However complicated the composition may seem superficially, you may treat it simply. You will control it by not considering any part as of any importance in itself, but only as it helps the whole; and you may strengthen or weaken that part as you need to. Don't cut the thing up too much. Let a half a dozen objects count as one in the whole. Mass things, simplify the masses, and make the elements of the masses hold as only parts of those masses.
Study placing of things in different sizes relative to the size of the canvas. Make sketches which take no note of anything but the largest masses or the most important lines, and change them about till they seem right; then break them up in the same way into their details. Apply the steps suggested for drawing to the study of composition, searching for balance chiefly, or for some other quality which is proper to composition.
Line.—Each of the main elements of composition can be used as a problem of arrangement. You can study composition in line, in mass, or in color.
"The Golden Stairs," by Burne-Jones, is almost purely an arrangement in line, and beautifully illustrates the use of this element as the main æsthetic motive in a picture.