Whenever I come to a hotel room, I first need to check if everything is right. Do I have light, power and warm water? Does the toilet work, is the bed tidied and doesn't the room smell strange? Do we have good Wifi reception?
Next I check if it's silent and can be made dark at night. I really hate noise when sleeping so I routinely unplug power supply for fridges or TVs with LEDs blinking all night. Usually I need to turn off a thermostat to find sleep. Sometimes it can even happen that the room next door contains the heating or air conditioning engine which may make sound day and night.
If anything is really bad, I need to request a different room before I made myself comfortable there. What do you check?
One think I always do at the first day, is to walk down the stairs, so I know the way in case of an emergency. Depending on the hotel layout, it can even be more convenient to take the steps next to my room than walking a long way to the lifts.
When choosing a hotel, I usually check if they have a lift, a restaurant, a 24h reception for checking in & out at any time, Wifi and free parking if possible.
What criteria do you have?