I'm happy to give you ideas, but I need to know what type of job would you do in the hotel?
"Can I help you?" (Very useful general question, also means "What do you want?" in a polite way)
"Was everything ok for you?" ( if guests have finished a meal, or are checking out of the hotel)
"Can I get you anything else?" (while guests are eating, or at the end of their meal)
"Allow me" (guest starts to do something, you're offering to do it instead. Like carrying bags, moving something etc)
These are all polite things to say.