In a small bowl, dissolve the sugar in warm water, then sprinkle the yeast on top. Let it sit for 5-10 minutes until foamy. In a large mixing bowl, combine flour and salt. Add the activated yeast mixture and olive oil (if using) to the dry ingredients. Mix until a rough dough forms. Knead on a floured surface for about 8-10 minutes until smooth and elastic. Shape the dough into a ball and place in a lightly oiled bowl, covering with a damp cloth. Let it rise in a warm place for about 1 to 1.5 hours, or until doubled in size. Preheat your oven to 375°F (190°C). Punch down the risen dough and shape it into a loaf. Place it on a baking sheet or in a greased loaf pan. Cover and let it rise for another 30 minutes. Bake in the preheated oven for 30-35 minutes until golden brown and the loaf sounds hollow when tapped. Remove from oven and let cool on a wire rack before slicing.