1997 Ford Ranger

Check for voltage at the starter while someone attempts to crank the car; if you get voltage at the starter but starter doesn't engage, replace starter. If you get below 10V at the starter, it's not enough to engage it, and at this point you would need to do a voltage drop test on the ignition circuit to find which component is defective.
If you don't have voltage at the starter, check your solenoid, clutch pedal safety switch, and ignition switch.
By the way you shouldn't be able to remove the key from the ignition when the car is running.