It usually depends on the person, the group, and the place.
If it was a room full of deaf people that weren't paying attention, just flip the light off and on once... not repeatedly (it's annoying).
If a deaf person doesn't respond when you call his/her name, simply give them a gentle tap on his/her shoulder... not pat his/her head, or poke repeatedly, etc.
If you're standing at a distance from a person and can't immediately tap his/her shoulder, a simple wave might help if he/she happens to look in your direction... there's no need to go waving your arms in the air like a raving maniac (especially in public places like at the mall or a crowded classroom). If that fails, then you can let it go or take the time to walk up to that person. This is like calling out a person's name. It's embarrassing to yell out a person's name in a mall as well as flinging your arms like crazy in a mall.
Just because a person is deaf doesn't mean you can go ahead and say whatever you want as if that person doesn't exist. There are different kinds of deafness... some are profoundly deaf and some are mildly deaf. They might be able to hear you in some way or read your lips. It's also kinda rude to be talking about something like that in front of another person as if he/she doesn't exist. Here's a good example...
What the Deaf Man Heard.
When a person is deaf, don't immediately assume that the deaf person can't do anything or is limited to a lot of things. If you're afraid to make an inappropriate approach, then try a neutral approach. For instance, just because a person is deaf doesn't mean they can't use the phone. It's better to ask if they can use the phone instead of being direct both ways. Saying "Oh, I better use the phone instead" might suggest that you think they can't talk or saying "Ok, you use the phone to order pizza" might suggest you aren't being considerate of their deafness. It's more likely better to say, "Could you order pizza for me?" That gives the deaf person the option of using the phone, using the TTY, the online/TTY relay, or saying "Sorry, I don't have the means to order. Could you do it instead?"
There are a lot of other things, I can't think of right now.
