There is a starter relay that the battery cable goed to and then on to the starter, sometimes they go bad. You can take 2 screw drivers or a heavy wire and jump across the two big terminals in the relay and the starter should turn, this is just a test to see if it will make the starter turn. If that don't work, it could have a bad starter. If it does work then the relay may be bad or the safety switch on the gear selector could be bad and not letting power through to the starter. Also make sure the terminal ends on the battery are clean where the terminals meet the battery post.
