I've said this earlier, I am not a police officer but I work at a police station and work with officers all day, so I see what they have to go through (they keep trying to recruit me, but F that its really tough and takes a special personality and attidute to stay in the job until retirement.)
One thing that you need is stand up grappling, for clinch control, take down, joint manipulation. Never arrest someone by yourself if you can help it, especially a drunk or a bum/crack addict. If its a serious arrest, and that guy comes come back in as a violent felon, they will call as many available officers to arrest that guy as possible.
Carry a tape recorder with you if your department doesn't already require it, it will save you and your station from legal problems. Depending on your department and your state, use that tase-gun when you have non-compliance, use your gun for ANY kind of weapon threat, especially a knife....very dangerous. Don't wrestle with a guy for a knife, jump away, unholster your gun. If you know knife disarming techniques, use them if you can't get to you gun in time.
Ummmm, thats all I can think of for now. Good luck and have fun being a police officer!
PS: Cops should really have the option of KOing people.