Pretty simple – a hotter oven makes better pizza. Preheat the oven for long enough so that your pizza stone or steel gets to the top temperatures. Around 30 minutes minimum, but the best pizzas I’ve made are always where the oven has been on for an hour or so. If you don’t heat it long enough, you get less oven “spring” – the action that happens to the dough when it hits a hot oven and puffs up before it hardens. You will probably end up with a doughy pizza base too.