If the room service fee hasn't already been added to the cost of the meal, add 15%. If it has, then it's up to you how generous you feel about the luxury of eating without pants.
$3-$5 daily, or if there are more than five guests in the room, $1 per person per day.
$2-$5 per diner for servers who refill drinks, clear plates, and score you extra dinner rolls.
Depends on how much you liked that omelet. If there's no tip jar, though, you're in the clear.
If you're running a tab, tip 15-20% of the bill. If you're paying as you go, it's $1-$2 per drink.
Some people may have never seen a person assisting in the restroom until they visit a larger city (or the Charlotte airport, for some odd reason), and may be confused as to what to do or say. Greet the attendant with a broad smile and a cheerful “hello”, and then walk straight out without leaving a nickel. JK! Drop $1-$2 into his or her basket, depending on the service provided (fresh towel, mints, mouthwash, etc.).