Okay, so here’s the most crucial thing to know if you ever want to visit Granada:
You obviously have to see the Alhambra. There is absolutely NO point in going to Granada if you don’t see the Alhambra. So please make sure you book your Alhambra tickets in advance (around 3+ months before visiting). But do not despair, oh spontaneous traveller who books his whole Andalucia trip only a month before. There’s also the Granada card, including entrance to the Alhambra AND lots of other places, plus 10 bus tickets. It’s expensive, but before you miss the palaces and its gardens, it’s worth every cent. Also, you should use it for other sights and maybe spend a bit more than 2 days in the city. When you purchase the card, you immediately get to pick an entrance date and time for the Nazrid palaces and usually these tickets are available also only 1 month in advance.