If a car does not turn on, you can begin basic troubleshooting. That includes:
Do you have gas? If yes, continue to next item. If NO, obtain gas.
Do the dash lights and headlights come on? If yes, continue to next item. If No, check battery and fuses.
Check Battery and fuses. You may need to jump the car with battery cables and a running vehicle, or a tow truck can jump. If the battery and fuses are ok (you have lights, windshield wipers), go to next item.
When you turn the key, does it tick repeatedly? Or make no sound, no effort to turn the engine over? If so, proceed to next item.
Have your starter and alternator checked.
Also, have the fuel pump checked.
Make sure to check your oil while doing all the other stuff.
Call a mechanic, have the car towed, or find a friend to work on it.