Photographers can just point and shoot to create objective pictures, or they can change a picture's properties to make it more subjective. The difference between these two styles is that objective photography tries to show the world as it really is, while subjective photography tries to show the world as the photographer herself sees it. Specific aspects of a picture that can make it objective or subjective are angle, tone, color and intent.
The angle of a photo can give the viewer an illusion of personal experience (subjective), or of being an external observer (objective). To make a camera angle subjective, the best idea is to take a picture on an angle that lines up directly with the subject's face or eyes, such as the camera on a roller coaster. On the other hand, if you want to make a picture objective, it is best to use an angle that makes the subject look like it does not even notice your camera.
Changing a photo's tone to make it convey a personal emotion or idea is best done after the photo has already been taken. Because of this, it is important to take a picture with as many of its natural tones as possible. Ironically, then, to make a photo subjective by altering its tones after it has been taken, the original photo that you take needs to be as objective as possible. A smaller range of changes to tone can also be achieved by using different lighting or angles if you don't want to take a photo and then alter it afterward.
Similar to changing the tones after a picture has been taken, changing the color values of a photo will make it more subjective. The easiest way to do this is to take a regular photo and then change it from being in color to black and white. Using photo-altering software, you could also change the colors of individual objects in your photo to change their emphasis or presence.
A photographer's intent is just as important as the other properties that make a photo objective or subjective. After all, if you are going to be changing a photo after it is taken to make it more subjective, the best way to start is by taking a photo that will be easy for you to change. Having an idea of what you want to achieve with your photos will also help you to take photos that are more appropriately objective or subjective, because then you can set out with your goals in mind.