When faced with this kind of problem, the first thing you should do before any other troubleshooting is to engage your hand break. This is so the car does not start rolling while your attention is on trying to get the cylinder to turn.
- Insert the key in the cylinder, apply a bit of pressure to the key and turn the steering wheel left and right. This is to attempt to find a free spot for the key to turn. The very first reason for a still cylinder is that most cars have a steering column lock which can bind at any time. In this circumstance, persistent pressure would need to be exert against the ignition mechanism and until it gets a free unlocking space.
- In the case of an automatic transmitting car, ensure that gear selector is correctly moved to the park and or neutral position this is because some cars would prevent the turning of the key if the selector is in any position besides park or neutral. This has a common occurrence as most people easily overlook this it can be easy to overlook this when tired or in a hurry.
- Use a spray lubricant of electrical contact cleaner on the surface of the cylinder to flush away dirt, follow this up with a quick spray of silicone to lubricate it. Upon adding enough lubricant, try again.