Lines and curves

Lines can be used to direct the viewer's attention to a subject. The line may not be obvious, but it has to lead the viewer's eyes to where it is desired, if that is the intention. Lines themselves can be the theme of the picture.

Curves are just a subset of lines. For example, a winding road that leads away from the view, to a small house at the far end.

Here, the rope that holds the hot air balloon directs the viewer's eyes to the balloon, making it the main subject even though it's not occupying an obvious region of the picture. The subject is not that interesting by itself, so it helps that the sun rays are coming through the mountains in the background.

Reflection

Reflection brings a kind of symmetry to a picture, and it's often pleasing. It can also be used to create a bit of confusion for the viewer, such that it's not clear whether the picture is the real thing or the reflection of the real thing. Besides this, sometimes, due to the surface of the reflecting object, certain effects can be achieved. For example, a reflection of the mountains on a lake looks pretty normal, however if there's a ripple in the lake, then the reflection has curves to it, which might make it more interesting.

Reflecting surfaces are everywhere, so keep a lookout for them. Spectacles, a dew on a leaf, window of a car, puddle of water on the ground. Even the top of the car, as shown in this picture. A picture of the building alone is fine, however, the added reflection off the top of a car makes the picture slightly better.

Silhouette

Silhouette photos are obtained when you underexpose the foreground subject. Usually, a typical background for such photos is the view of the sky during sunset or sunrise. The typical subject for such photos would be people. The challenge is thus, to find alternative backgrounds and alternative subjects.

The main elements to a silhouette picture are the shape of the silhouette, and the colour of the background. Ideally, both should be interesting to make a striking photo.

Here, a silhouette of a Indian idol is set against the background of a sky with wispy clouds. The unusual shape of the idol plus the interesting sky background makes for a good photo.

Rule of Thirds

The Rule of Thirds says that when a photo is divided into a 3x3 grid, subjects placed at the intersection of 2 lines tend to be more pleasing to the eye than when the subjects are placed dead center.

My personal intepretation of the 'rule' is that - be aware of where you place the subject, and know that you do not have to place the subject in the center everytime. Explore the spaces between the center and the borders of the picture. Also note that when you place a subject at one of the intersection, the opposite space needs to be
'balanced' somehow. It's hard to describe what this balance means. I will try to touch on this in the future.

Here in this photo, the two towers along the Great Wall of China are placed roughly at the locations deemed ideal by the Rule of Thirds.

Colour

One of the elements of a picture is colour. Colour itself can be the theme of the photo. Contrasting or matching colours can produce great pictures by themselves. They can also evoke certain emotions in people - for example, red invokes feelings of danger, passion, stimulation. Be aware of how colours affect the mood of the picture.

Do take note that exposure affects the tone of the colours, so be sure to set the right exposure. Nowadays, with digital cameras, one just needs to review each shot and adjust the exposure accordingly to desired effect.

Here is one photo which I think shows the concept of using colours as the theme. Of course, it will be better if the colour theme is mixed with other concepts like shape, lines, texture etc. Always keep a lookout for subjects with good colours.