Typicaly, in most of the better roleplaying games I've been in, combat goes somthing like this:
DM: Ok, Dave your up!
Dave: I try to hit the Orc. I rolled a modified 22! If that hits, the damage is 9 hit points.
DM: Great! You cut down the orc like a sheaf wheat. Lou, your next.
Lou: I attack the other one. I rolled an 8.
DM: You miss. Its the orc's turn.
Many things cause an attack to cause no dammage, too often attacks that cause no dammageare just dismissed as a miss. but in reality many things cause an attack fail. Here are some examples to spice up your combats.
1. The Whiff. Simply put, the target isn't where you expcected it to be. You swing your weapon and hit nothing but air.
2. The Dodge. The target moves out of the way of the attack, good for a dextrious enemy to use.
3. The Parry/Block. The target activly puts something between the attack and himself, most often a shield or a weapon. It tends to be very common for people with shields, or ones that use two weapons but not limited to them.
4. The Glance. The attack hits the target, but skipps off the armor. Some armors are designed to make sure no hit lands cleanly.
5. Absorbed. The atttack hits but does no dammage. This could be that the armor is thick, such as on a dragon. It can also be used for any type of worn armor too.
6. The Graze. The attack hits and causes no damage or superfiacal damage. I'd use this for an attack that just barely missed, maybe descipbe a cut on the cheek or the ear.
Anything else would be a normal hit, so take my advice. Go out and making missing exciting!