I know it is common sense but you really would not believe the amount of singers who ignore these very simple rules to avoid abusing their voices.

Decrease your overall volume.

Don't shout or yell

Don't whisper! It may actually make your voice worse.

Don't talk in the presence of a lot of background noise! Talk to someone only when they are an arm's length away.

Don't try to talk or sing when you have a bad cold or laryngitis.