Make sure you drink bottled water all through your hols and brush your teeth with it too. Best not to eat too much salad. The fish is good and the Odjo d'Agua Hotel is superb for a meal overlooking the ocean. Book a table in advance. Not necessary but a good idea at the week ends.
The Yellow Submarine, Glass bottom boat is good. There is a statue of Christ in the sea. But if you tend to get sea sick, don't go on the boat, it's a bit like a cradle under the boat that swings back and forth and can cause queezineess! The catamaran is fine but you can go out to sea and see nothing except ocean and no dolphins. Ask locally first. Bear in mind also that if there is only yourself going on the trips, they can be cancelled. Don't let this happen INSIST - they advertised it - it's not your fault if they can't get enough people to take you. Don't be let down.
Cape Verde is very different. Best to find a hotel near town as the other hotels are well out of town and isolated from the tourist areas. The Porto Antigo is good if you take an apartment, but if you take a studio for two people, the sofa bed is VERY uncomfortable.
Hope to put some video soon on YOU Tube.