Don't leave any food out for her for at least 2 days. This way when you set the trap with sardines (they LOOOOOVE them!! The smellier the better! )

Cover the trap. Put a tiny big of sardines on a piece the paper plate in the shape of a pie slice. Put it in the furthest corner of the back of the trap. Remember to also cover the grates on the bottom of the trap where they will walk near the trip plate. Check the trap often. There may even be more than one. So it's best to set the trap one more time AFTER the cat is caught. Just to be on the safe side.

Good luck. Keep us posted.