To rise quickly and be light and fluffy after baking, your dough needs perfect temperature during resting time. Optimal fermentation range is between 27ºC and 40ºC. In summer, it works well to rise your dough in the sun. In winter, place it next to a radiator. To me, the most tricky is time in between seasons, without direct sunlight and without heating working yet. Then, I place my dough in the oven on the minimum temperature mark. It cannot be more 50ºC, though, or your yeast will get killed in the process.