Those of us who fly a lot will know that there is a bit of a variety in cabin crew. Some (sadly more common on certain airlines) do the very bare minimum to ensure a safe flight, but nothing more. Many (especially on airlines noted for good customer service) provide a good service.
Every so often though, you come across a flight crew who go the extra mile. These are the ones always friendly, always helpful, always thinking ahead and solving the problem before it has happened. One moment they're serving you your drink, the next reassuring a little old lady about the flight, the next magicing a colouring book to turn an impending toddler crisis into a happy small child, then answering queries on arrivals and immigration for a first time travaller, then back to offer you a top up of what you're drinking (which they've remembered exactly). Not very often found, but very much appreciated when you happen across them on your travels!
In the case when you do luck out and find yourself on a flight with a great cabin crew (who go well beyond what you normally experience as "good" on that airline/kind of airline), is there a standard/common way to recognise them at the end of the flight? Not just to thank them then and there, but also to let the airline know that this person/group are what the rest of their staff should be aspiring to. Is there any standard way, or does it vary entirely by carrier?