If the restaurant has name tags, getting the names is easy. Definitely get the name of the server. If the server doesn't give me a name, I usually ask. A description is usually okay for the hostess, UNLESS the directions specifically say you need the name. If the manager has a name tag, get his or her name. The server's name is usually on the receipt. Although a couple of MSC's instructions tell you to ask the name of the manager on duty, most are fine with a description if there is no name tag. Description is fine for the busperson unless he is wearing a name tag.
I do a lot of restaurants. When I first started, I used a 3X5 index card with fill-in-the blanks for necessary info to be sure I didn't miss anything. Now I just notice and remember. It won't be long before it becomes second nature to you. Your eye automatically jumps to a name tag. If there's no tag, you think "female, long blonde, bun, 5'7", 30, large hoop earrings" or "male, 6'2", 35, long black, ponytail, mustache, beard, glasses." It gets easier.