#1 Color:
Color is one of my favorite things to play with when taking a picture, and its one of the best ways to liven up a dull picture. Bright colors really draw the eye into the picture and create interest. Red, yellow, orange, and even a bright blue sky can really enhance a picture and bring a fun mood to the picture. One caution when incorporating bright colors into a picture is to be careful not to bring to many colors into a photograph, one or to is usually enough.
#2 Texture:
Texture is a great thing to look for when taking a picture. It helps to add depth to the picture. Texture is especially usefull when you are looking for a background for a portrait. If helps to add interest to your picture. Texture can be found in stones, bricks, sand, old siding, cracking paint, and a multiple of other places. Keep your eyes open for texture and what once was a boring face shot will really pop!
Also check out: 100 Terrific Photographic Textures
There are different types of lines to look for when taking a picture. The most common is what is called a leading lines. The picture to the right is a perfect example of this. The line draws your eyes to the subject of the picture. Leading lines are very useful to a photographer because it is one of the ways that a photographer can control where his/her audience makes the center of attention. Another good thing to remember when taking a picture with lines is if at all possible try and find an angle where the line is not in a straight line. This helps to add interest to the picture.
Also check out: A Guide To Leading Lines In Photography