First, what is the aim? Are you looking to maximize your personal safety or minimize the chances that something will happen to your car?
Strategy #1: Minimize the chance of an incident happening with your car.
The spaces closest to the entrance will be high volume, high turnover spaces. Your car is most likely to get new dings, scratches and dents here. It's more likely somebody will back into your car here. And it is more likely somebody will see something inside your car, smash the window, and take it.
A better parking spot will be up a few floors on the downward side of the garage in one of the end positions, so that only one side of the car is exposed to door dings. And in those spaces you can allow for more space in that area.
Look above you, make sure there are no leaking pipes.
If it is raining, make sure no leaking water is coming through seams in the concrete decking above. If water is leaking in that area, then move your car, because water mixing with limestone can put a permanent stain in your paint.
Always hide all things of any value. Don't leave your GPS device out. Don't even leave spare change visible. Car windows do get smashed open for the spare change in a cup-holder. It happens.
Be sure all your windows are up. Lock it. Take note of your exact position and your exact floor.
Snapping a license plate photo of the cars parked next to you could be helpful if there is a damage incident.
With many garages you pay at an electronic kiosk in the main floor area. So you'll probably need to take your time-stamped entry ticket with you in order to pay quickly when it is time to leave. Don't lose the ticket.
It's probably safer to use the elevator, not the stairwell. Sometimes bums make a home out of parking garage stairwells, especially the less frequently used stairwells. Older garages have enclosed stairwells. These are more dangerous and more isolated. There's a chance surveillance cameras will be in the elevators though and these are more frequently used = greater safety.
Strategy #2: Maximize personal safety.
Using a valet parking service is safest. You wait for your car in a safe place where other people are around. It is one of the main advantages of using a valet parking service: personal safety.
If using valet is not an option, do some prior research on which garage to use. You want to choose a convenient garage where an attendant will be available to walk you to your car. If possible, speak with the facility manager and ask if there are any brand new workers. Ask what kind of screening they did with this new hire. If you are satisfied with the answers, that's where you park.
Parking in the ground floor high volume spaces will be ideal.
If you are going to another parking deck, keep your doors locked while surveying the situation. Take a good look with who is nearby. If the vibe seems okay. Park. Be sure the car is locked up and secure. Then walk briskly to the exit or elevator.
Stay off your phone until you are certain you are in a safe place.
If somebody is asking you what time it is, you are probably about to be robbed. Don't talk to them. Keep walking.
When it is time to leave, don't worry about if you are bothering the parking attendant. Ask the employee to escort you to your car. When you are close to the car, but not too close, thank the person. Perhaps offer a gratuity.
Get in the car. Crack the window open a little to hear approaching cars. No radio volume. Keep doors locked. Start it up and go.