And we were not dissappointed in any single step of our trip...
To see. As above, those are really all the must see places. Comino island visit can be combined with visit to Gozo island, while Valletta and Mdina are 2 towns to dedicate 1 day each... Fish market works only Sundays, so you need to plan your trip accordingly.
To Stay. Higly recommend to find some small house to rent near the see. We rented a family house in Marsascala (we were 11 souls). Service is excellent, and views from the terrace unforgetable.
To eat. Any of family run restaurant is excellent place to get fresh sea food and home wine.. (Chardonay and Merlot are indeed best choises from local wines)... For 12-15 eur per person one may get really excellent cusine. Local rabbit is must try!
To know. You do not really need to rent a car. Island is small, and bus system is well developed. Car will only add stress to navigate through the net of one way streets... And for gamblers, rules in local casions are tough to win... 3 card poker seemed best value for money :)