After some recent traveling, I've seen some rather appalling hotel behavior. Here are our tips!
1. No unnecessary complaining. If there is something seriously wrong such as a lack of towels or toilet paper, request some more. However, not liking the shampoo and conditioner doesn't call for complaining. (Yes, I did happen to overhear someone complaining about this to the front desk.)
2. Smile and express thanks. Did the manager upgrade your room free of charge? Thank him or her when you see him. Things both ordinary and extraordinary call for thanks! I guarantee they don't hear these things as often as they should.
3. Don't be too loud in the hallways or the rooms. People could be sleeping, on the phone etc. Beware especially at late hours! You wouldn't want to wake up a sleeping toddler!
4. Follow the Check In/Check Out times. Self explanatory.
5. Don't leave the rooms too messy for the staff. Self explanatory again.
Keep minding your manners!