The man in control cannot lock both hands together while on the ground (Unless he is using a pinning combination).

No stalling (meaning not trying to gain control or go for the pin-points)

No Slams (No picking someone up in the air and dropping or throwing them in way that might be dangerous)

Don't be a jerk, shake your opponents hand.  Have good sportsman's ship.  You can always throw your headgear somewhere else after the match. :)