As a rule of thumb, to avoid messing too much with the levels afterwards in PS
, it is good practise to have a look at the histogram on your camera when you are shooting. Most DSLRs support this feature. By looking at the histogram you will know instantly how to adjust your exposure. It is a lot easier than judging the exposure by the picture in the little LCD
screen on the back of your camera.
Another usefull feature on many cameras is the "show the blown out whites by flashing". Using both features together will give you less work in PS
Never be afraid of what you like. (Miles Davis)