Focus is critical, pixels are cheap
If you are shooting wide open, which is at the camera’s largest aperture, your depth of field will be correspondingly shallow. That means your focus is going to be even more critical than otherwise. Pick a point that needs to be sharp and really pay attention to keeping that point sharp. Generally, if you are shooting people, the most important thing to keep sharp is the eyes. When I am shooting people I focus on the eyes, shoot, re-focus and shoot again …and then do it all over again. I can’t tell you how much I hate to be editing and find that I have a potentially great shot, but out of focus eyes ruin the picture. I have found that if I am worried about an image not being sharp, I am usually right. Pixels are cheap…shoot enough to make sure you have your shot!
Shooting for stock, know your equipment, know your agency
If you are shooting with a stock agency in mind it is good to know just how high you can push your ISO before you reach the point where the agency is going to reject the image. That means you have to know both your own equipment and the standards of the agency. I was once shooting from the interior of a jeep on a mountain road in China. The scene, road-building equipment clearing a landslide, was lit by the headlights of the cars waiting for the road to be cleared. I shot the scene, hand held, but braced against the head-rest, at an ISO of 1600 with a Canon 1ds. Man did I work on that image in post (processing the digital files)! They accepted it too. With the newer cameras I have no qualms about shooting at 400, I am comfortable shooting at 800 and don’t think 1600 would really be such a stretch. But don’t take my word for it… do some testing!
Exposure and more
RAW (the file format native to the camera) has been talked to death,