How can I tell if a hotel room is clean enough before I unpack my stuff?

The first thing I do when I walk in is smell the room - that stale odor or mustiness tells you way more than you'd think. I stayed at a place once that looked fine on the surface but smelled off, and when I checked behind the nightstand there was visible dust and what looked like old food crumbs. Beyond the mattress seams that others mentioned, I always run my hand along the top of the AC unit and check inside drawers and under the desk for debris. If something feels off, ask for a different room right away - most hotels will switch you without hassle, and you'll sleep way better knowing you picked somewhere actually decent.