As suggested I would go to the St. Davids area where you have the cathedral and there's St. Nons Well/Bay. There are too many bays with great photo opportunities to mention in this area. Near to Fishguard you have Strumble Head light house, Pwllderi is well worth a visit for the views, great sunsets, and to the North of Fishguard you have Dinas Island, (a headland), where you can do circular walk around the headland, start at Pwllgwaelod or Cwm yr Eglwys.
Lots to take pics of in the area, I'm off that way in August for a hol. have a great time.
Regards
Ray