* Shift lever: Make absolutely sure the shift lever is fully engaged in park. Try gently rocking the car back and forth a little to see if that helps settle it. Sometimes a small amount of debris can interfere.
* Brake pedal: Ensure your brake pedal is firmly depressed. Some cars require this to release the key.
* Steering wheel: Try gently turning the steering wheel back and forth. Sometimes a slight lock in the steering column will prevent key removal.
* Broken shift interlock: This is a common problem where the mechanism that prevents key removal when not in park fails. This will require professional repair.
* Other obstructions: Look closely around the ignition. Is there anything stuck in there preventing the key's release?
If none of these solutions work, you will need to contact a locksmith or your car's roadside assistance service. Attempting to force the key may damage the ignition, causing more costly repairs.