A root canal procedure is a fairly common procedure, especially if there is a family history of bad teeth or you are middle-aged or older. As such, you may not be as concerned about the procedure as you are leading up to the procedure itself. There are actually several things you should and should not do with a tooth that will be excavated and operated on.
Things You SHOULD Do
As you prepare for your root canal, do not avoid oral hygiene practices unless directly instructed to do so by your dentist (and not many dentists are going to tell you not to brush the rest of your teeth). Your severely damaged tooth is probably incredibly painful, so you do not have to brush that tooth if you cannot stand the pain. Do, however, floss around this tooth and brush the rest of your teeth as you normally would.
If your dentist says it is okay, use an antiseptic mouthwash. The antiseptic properties may help fight off bacteria that could otherwise cause your post-operative root canal to become slightly infected. It is a matter of opinion among dentists, so check with yours first before you use an antiseptic mouthwash.
If you can, avoid chewing on that side of your mouth. Most people can do this and because of the pain they experience, they are often willing to oblige. This will also help keep food particles out of the gum tissue and out of the damaged surface areas of the tooth (if there are any).
Things You SHOULD NOT Do
As for the things you should not do to a tooth that is about to undergo a root canal, you can start by not attempting to pull the tooth. This could make matters much worse, and attempting to pull the tooth to avoid a root canal or reduce pain is just unwise. Part of your tooth is still very much alive, and your dentist wants to do a root canal so that the tooth might be saved.
Do not take any aspirin for pain. If you are not already aware of the fact that aspirin is a blood thinner, you would be when the dentist gets down to the blood vessels inside the tooth and there is suddenly a lot of blood to stop up. This could seriously complicate your procedure to the point where the dentist may choose to postpone it.
Finally, do not apply ice packs or ice directly to the tooth and surrounding gums or utilize any sort of home remedy without first asking your dentist. You do not want to have an adverse reaction to the root canal procedure because of something else you did pre-procedure that you should not have done. If there is any sort of remedy that you want to apply but you are not sure if it is allowed, err on the side of caution and just do not do it.