Submission is a non-contact sport and the one of the ways to win a fight is to hold a person until he decides to tap the mat or says so. To give you an idea, here are a few popular submission techniques.
The first is the shoulder lock. Here, you are holding your opponents shoulder up while at the same time lifting his head off the ground. A lot of wrestlers have said that this move is more effective than the wrist lock since the pain is centralized only on the tendons of the elbow.
Next is the Standing Heel Toe Hold. While the opponent is on the ground, you hold one of foot using one of your feet while the foot is on the mat for better leverage. You then grab the other leg which he will probably try to kick you with putting one hand holding the toes and the other hand under the opponents Achilles tendon. If this is done correctly, you are able to put considerable torque on your opponents ankle.
You also have the double wrist lock. This hold can be executed while you are lying on top of him or while you are standing. Once you are able to grab one of your opponents wrists using your opposite arm, you use the other one to reach over and lock it....