Here's a tip: C&D is good, don't get me wrong, but if you can put on a good act, using the Dead Ringer will get you kills like i don't know. Jump up and down running backwords toward the enemy screaming medics works and regular people, not on hardcore players though :( If you do this, don't run away frantically unless you're set on fire. If you are set on fire, get out of range, jump and activate the watch.
:D