Most know that composition is important in a painting, but they may not understand how to achieve a good composition. It is so important that there have been books written entirely on that subject. Many books. But take heart, it can be broken down and more easily understood. Let's see if I can help you out.
For starters, I will say that composition is important enough that it can make or break a painting. A painting can be average in skill but have a strong composition and it will win a prize. On the other hand, a very well executed painting can fall apart if the composition is lacking. The composition must be very strong and there are several types to learn. But only a few are necessary to begin with. The "Center" composition, the "S", the "L", and the "Triangle" are examples. I will describe each below.
You may remember that I have mentioned before that the focal point follows the rule of thirds. If a paper is fold into thirds horizontally and lines drawn along the creases, then folded in thirds vertically and lines drawn again on those creases, the lines intersect at four places. Those are the locations of the focal points on a canvas (approximately) You can draw these lines on a canvas, but it is not really necessary. The location doesn't have to be EXACTLY on that spot. I have a photo below to illustrate. Of course this is not a hard and fast rule; there are exceptions to every rule, so to speak. But generally, the focal point, or center of interest usually falls in the general area of these spots on a canvas.
The composition comes in when we design how the eye gets to that focal point. We do that by means of a road, a river, a pathway, trees, etc. For instance, the most simple composition is the "Center" composition. It is usually only used for portraits or florals. Of course the focal point is never strictly in the center. It is off center slightly to be pleasing to the eye.
The next one is the "S" composition. It is also simple. The eye follows a curving road, a river, pathway, etc to the focal point. (see photo)
Another one is the "L" shape. This is usually a very simple painting with a taller object and something long and low beside it. An example would be a windmill with a water trough beside it. It can even be a large tree and the shadow it casts on the ground. The sky and other trees would be very simple behind them. (see photo)
The "Triangle" composition is more complicated. There are three different types of "Triangle" compositions. The first shows the focal point in the center of the Triangle. The surrounding objects "frame" it in a Triangle shape such as trees, water, grass, clouds, etc. (see photo)
The second Triangle is where the focal point is on one of the triangle lines and the other two lines follow the surrounding objects. (see photo)
The third involves triangles of lines leading to the focal point. For instance, the tree line, the road, a hill, even rocks along a stream all subtly point the way to the focal point. This is probably the most complicated of the three. But if well done, it is very beautiful! (see photo)
There are other types of compositions, but these are plenty to start with. You can do some research on your own and see how many more you can come up with, OK? Hint: several are letter shapes! I hope this has helped you to wade through the subject of composition and come out with a better understanding that will help you in your art endeavors. See you later!