Keep eyes in focus
This is a very important thing when taking pictures of people and animal. If something has an eye, it must be in focus or the brain interprets the whole image not to be sharp. From evolutionary point of view, we are used to making contact with the eyes first and then expanding out to the rest of what we are seeing.
Obviously, you achieve this by making sure your camera focuses on the eye(s). If you leave your camera in automatic however, it will choose its focus point, not you. It will often look for areas of maximum contrast and focus on that, literally. You need to find the menu option that lets you select the focus point and use that force the camera to focus on the right area. This unfortunately is not available on low cost cameras.
Now, even if you have the focus point, it is still possible to wind up with eyes out of focus slight due to camera focusing error, subject movement, or camera not having enough time to focus. And advanced trick, which I won't drill into here, calls for selecting just the eye in a photo manipulation program and sharpening that portion more! And with it, making the image right again (sharpening an entire image might create too many artifacts elsewhere).
See this example of "street shooting." If I had let the camera pick something, it may have opted for the foreground image:
Canon 1D MK II, 70-200 F4 shot at F4.5, ISO 500, 1/125
Note that I only had a short second to take the above picture as these are street fashion girls in Tokyo who are doing their own thing and rarely post for you (and when they do, it is an awful artificial pose which I avoid). Yet I had made sure I had her eyes in focus.
And another:
Canon 1D MK II, 70-200 F4 shot at F4, ISO 200, 1/400
Now, I should put a disclaimer I should have included in the first post. Sometimes you want to break these rules. I would say you better first master the rule and then figure out when it makes sense to break it. Only then will you appreciate if the image with broken rule is better, or flat our wrong. See this example:
Canon 1D MK II, 70-200 F4 shot at F4, ISO 640, 1/125
I just love this image. It emphasizes the Japanese female fascination with treating their cell phone as jewelry with ornaments and such and yet, it brings the feel of the way they wear their street fashions. That said, if I asked my wife if she likes this image, likely she would ask for a version with the girl in focus.
What do you think?