One more idea that fits nicely into anybody’s website development kit…
There exists a rough sort of principal that can be applied to the process of composing most images, whether a still-life painting or a landscape photograph: The Rule of Thirds. It goes like this… Imagine the picture area is divided both horizontally and vertically into thirds. In other words, a 3×3 grid. If you start with a rectangle, your grid will be made up of smaller versions of this rectangle. Start with a square, and you’ll have 9 smaller squares. Simple enough, right?
The general idea is that your subject matter should (roughly) fall along the lines of this 3×3 grid. Don’t get fussy. There is no need to get out measuring devices and calculators. This is not a hard-and-fast rule, but rather a general guideline. By simply placing your subject matter somewhere along the grid lines–you immediately start to set-up “harmonic” relationships between the elements within the picture area; both part-to-part and part-to-whole. Just as in music–the elements of a chord may be either dissonant or harmonic depending on the relative intervals. It works the same way, spatially, in the visual arts.
Now, having said that, please understand that this is just a beginning and NOT ALL subject matter will lend itself to this rule; but, many will. The more you work with composition, the better you’ll get at reading a motif. The art of composition can be as complex and subtle as you wish to make it. There are far more variables to a composition than the simple spatial ones I’ve mentioned here. But for those just starting out, this can be a wonderful beginning toward developing one’s own sensibilities for composition.
P.S. – Taking the music analogy one step further: Just as an inverted chord sounds “right” in music, a successful visual composition will “work” turned upside down. If you are being challenged by a composition; but, you aren’t sure where the difficulty is coming from — try turning the image on its head: The spatial intervals are more easily seen when they aren’t competing head-to-head with subject matter. Try it sometime. It works!