1. Never use your lowest or highest aperture (f-stop) setting.
2. All things being equal, most lenses are at their sharpest at f/8. If depth of field (DOF) doesn't matter, use f/8.
3. For portraits and people pics, use a small DOF and focus on their eyes. For outdoor/landscape, go with smaller apertures, but not f/22 (see above).
4. If there's not enough light, get more lighting. If it's still not enough, change locations. If it's still not enough, put the camera away and try again when there's more light. After all that, if you absolutely have to have the picture, then it's OK to use a flash.
5. Play around and practice a lot. Photography technique involves lots of balancing between lighting, contrast, exposure, perspective, motion, DOF, and color. If you have the gift, you won't need lessons--just practice and experience.
6. Be prepared to throw thousands of dollars away on this hobby if you get wrapped up in it. When you get a great shot, though, it's worth every penny.
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