Ideally, just... check in.
But, there is a significant number (IMO) of untrained desk employees out there, so I hand over my credit card (HH AMEX, of course - points don't grow on trees!) and my status card as I check in, and say something like "I think the numbers are all there..." This has helped a couple of times when the tired / burned out / new / untutored / harried agent looked up and got a tiny glow of recognition in the yes, shuffled records and did something nice for me. And a "smile and ask" routine does well too.
As opposed to hotgluing the card to my forehead, sweeping my coat over one shoulder and and announcing in stentorian tones "Ta-DAH! Lookee here, folks, an HHonors DIAMOND has arrived!"