They don't take reservation for the outdoor seating. Just tell the waiter you want a table and stick around until he calls out your name. It's worth it though. Try the pasta with swordfish.
Almost always fully booked inside. Get there 10mins before opening and be at the front of the queue for the outside seating, but watch out for people squatting on the tables.
The worst dinner i had in Sicilia.No proper service,food is not fresh. We all got sick the next day. I think the reason is it has good location for tourist. Never come again!