Hand pollination can be used to help improve fruit set. To hand pollinate, pick male flowers (sitting above a fairly thin erect stem), remove petals and gently brush over the centre of the female flowers (flowers sitting above a tiny swollen base). Do this early in the morning as the short-lived flowers can close by mid-morning.
Try watering the soil more than the leaves. Water sitting on the foliage all day can promote fungal issues, like powdery mildew.