Plain flour can be used for short crust pastry, sauces and gravies which do not need a rising agent. Self-raising flour includes baking powder, and is best for most cakes, buns, scones and puddings. It gives a better lift than a homemade mix of plain flour and baking powder, though that is suitable for mixes with eggs or egg whites, which encourage rising.
Gluten is a protein in flour that develops and becomes more elastic as the dough is kneaded. Strong flour has a large amount of protein, needed for pasta and bread making.
Use sponge or continental flour, which has less gluten, for light cakes and pastries. Sponges, cakes and scones made with soft, fine flour have a more delicate texture.