ATM card skimmers come in a variety of forms. NPR talked with an ATM technician to figure out the most common ways to spot skimmers, and it turns out you really just need to jiggle the equipment a little.
Photo remixed from William Grootonk.
On top of checking for cameras above the machine (or just covering your hand when entering your PIN), NPR says you need to look for two things: a loose card slot and a fake keypad. Essentially, if the card slot or the keypad seems loose, don't use the machine, because that's a telltale sign the machine is hacked. It's as simple as that.