Total Number of People
The first thing to look for is how many people are you having and how many camps will be needed to put in place. It is best that the camps are placed together for your convenience. At a campground, there are going to likely be more people so find a spot where you can have several camps put together. If you are alone, you can pick any spot regardless of the spot next to you is taken or not.
Closer to Facilities
The campgrounds have the basic needs for humans available to make it easier for the campers. There are cooking places available. In some cases, you may also have electricity outlets and other utilities available. It is best that the camp is set closer to the facilities at the campground so that you can use them without much trouble.
The camps are not always made on perfect plains. It is quite possible that the one you are camping on may be in a hilly area. Look for a spot that receives a good amount of sunlight during the day otherwise it could be a really cold spot and you may feel the chill at night. Make sure that the surface is good for camping as well.
Avoid camping in areas where stream might be running very close by. In case of rain, the water level can rise. Even if that does not happen, the soil that is already damp may get slushy and can leave you stuck for the night in muddy conditions.