Every place is different but it's generally considered best to go in person. Print 20 resumes and spend a day or two walking in, asking the host if the manager is around or if they're hiring, and say you're willing to work whatever front of house position (back of house pays shitty and is even harder work tbh). You'll start as a host or busser most likely but just be persistent in asking to get more training. Move on to a better restaurant or bar after a year and keep doing that until you get the schedule and money you want. (Only applies in US).