Turning the key to start the engine results in a rapid clicking noise, but it doesn't start.
It appears that your Toyota RAV4 is having trouble with either the battery or starter engaging the engine and allowing the car to start. The clicking sound you are hearing may be due to low battery voltage or to a failed starter solenoid. However to be 100% certain of the cause, it may be time to enlist the assistance of a certified mechanic to take a look at your RAV4. They will quickly be able to determine exactly why your Toyota is not starting and determine if it is the starter, battery, or something else entirely. They will also be able to make the necessary repairs to keep your RAV4 starting every time.