Format, don’t erase
If you only erase images from your memory card, you won’t wipe all the data and a “ghost” image can be left behind. This can add to the risk of data corruption. To make sure your memory card is wiped clean, always format, as this will completely rewrite any camera information.
Ascertain your camera’s dynamic range
Knowing the dynamic range of your sensor means that you can avoid exceeding it and losing highlight or shadow detail. There are a lot of ways of measuring dynamic range, but you’ll also find that many labs have tested a lot of digital cameras and posted figures online. Try DxO labs as a starting point.