If you are used to go to the church on Sundays, visit small church on the main promenade. There is Mass in several languages. When its sunny it is held outside so you will see many people gathered before the church.
In an evening the harbour and promenade area is a good place to sit with a drink in your hand and admire the view. Many of the locals (and some tourists) like nothing better than to have an evening stroll. This is a good place just to sit and watch the world go by.
There are a few restaurants, bars and ice creams parlours to sit in and relax. The atmosphere is very peaceful and the scenery is stunning.
Rabac has very nice small harbour with surprisingly clear blue water and even tiny beach. It is full of boats and definitely worth some photo :)