Choose a campsite with a level, smooth area in which to pitch your tent. Pitching your tent on a slope will lead to a night of tossing and turning as you roll gradually down the hill.
Select a site that isn't too close to the campground's bathrooms or trash dumpster, since these noises may keep you awake in the night.
Inflate a sleeping mat to your desired firmness. It's a good idea to make the mattress slightly firmer than you like in case any air leaks out in the night.
Choose a sleeping bag appropriate for the temperature you will be camping in to avoid being too hot or too cold.
Put your sleeping bag and pillow on top of the sleeping mat. If you feel yourself slide within your sleeping bag, that means you aren't on level ground. Move to a more level part of the tent, if possible.
Keep extra blankets handy in case the temperature drops during the night.