Last week I was in Sevilla for work for a couple of days, so we (my wife and I), decided to make a holiday of it and spent a week (7 nights), Sunday to Sunday.
We've been to Sevilla a few times before so this time we didn't go back to the Alcazar or Catedral - that's why they're missing below. It is not any suggestion that other people should also skip them. They are both "must sees" in my view.
The end of our week coincided with the Andalucia Day public holiday (28/2, but as that was a Thursday I think many took Friday 1/3 as a holiday too, to make a four day break). Andalucia Day is nothing compared to Easter Holy Week or Feria de Abril events. Nevertheless family crowds in the very centre were still large, at least compared to what I'd expect in late February / early March.
We walked past the Alcazar shortly before it opened on Friday and already the queue was very, very long. My advice is to buy tickets in advance for that, whenever you're coming. Away from the central sights, crowds were non-existent.
Hotel - we stayed at Hotel Inglaterra and it was ideal. But please note I suspect it can be expensive in main season. However, the time of year we went meant it was relatively cheap, plus we got a discount for booking 7 nights (and we got upgraded to a balcony room). So for under c.€80 per night, including both our breakfasts, we were more than happy. If the price were double that, as it can be in Spring, I might look elsewhere to save money. The location on Plaza Nueva is ideal for walking the central barrios, it's next to a tram stop and C5 circular bus stop and taxi rank for more distant visiting. Staff were helpful. Breakfast was very good. Importantly, our room had a kettle and tea supplies. Bed was comfortable and the shower powerful. There is air conditioning and lifts. Also a rooftop terrace (open to non-residents too).
Guides - for planning we used the DK book (which comes with a useful tear out map) and www.andalucia.com, which I always find helpful for visiting the region.