Lightweight but strong nylon fabrics produce tents that are easy to carry and survive vicious storms. Tents are either free standing self supporting or require staking and possibly guy lines for support. For backpacking, either is generally suitable. Free standing tents have the advantage of being easier to set up in very shallow soil, but in high winds the should be pegged as well. For winter camping and climbing free standing tents have a definite advantage.
Most tents have an external fly that covers the roof and walls of the tent.
The fly must be made of waterproof material and all seams and stitching must be sealed to be fully waterproof. The tent itself must have a waterproof floor which runs several inches up the walls with all seams sealed. Walls are generally made of a fine mesh or very breathable nylon, this allows the tent and occupants to breath. The doorway and walls not covered by the fly should also be made of waterproof nylon with seams sealed. Zippers should be the heaviest available.