We spent a few days in Seville a few years ago and had a lovely time visiting the city. I would highly recommend not staying in the touristy part. There are many lovely things to see and do, but you can tell the locals are annoyed by tourists and it’s very busy. We did have a waiter tell us to not leave anything out and they weren’t kidding! We had a cell phone swiped from the table we were eating at and we never even left the table!
Aside from that, there are lots of lovely parks, beautiful architecture and delicious food to eat! We found a lot of fun wandering around the city, playing at the Isla Magica amusement park, taking a carriage ride to the Plaza d’Espana, and exploring Sevilla Cathedral and the Giralda.