A couple places in the South part, but the main stop was to be in Barcelona for 5-6 days.
As for Barcelona, of course see the Gaudi buildings and Parc Guell.
Casa Batllo is a beautiful Gaudi building and hosts different parties that are open to the general public. This year's "Magical Nights" series features soul, jazz, flamenco, rumba concerts on the rooftop.
Find the best tickets/guided tour you can afford for La Sagrada Famiglia. It is even more spectacular when you learn more about it. If that kind of thing interests you, do some advance reading or YouTube on it and you will appreciate it more!
The Mercat de la Boquiera is like our St Lawrence Market, but even better! About the only market that I've been to that can compare is the Riga Central Market which is housed in 3 WW2 Airship Hangars.
I try to eat lunch there as many days as I can!
The Gothic Quarter is very nice to meander.
You have to do the Las Ramblas stroll but it's a bit much. Cool bird cages with birds for sale are something special.
Also, the beach in Barcelona is packed with hot women!
Another less touristy place just outside of Barca is a beach town called Sitges. It is known as a gay place but don't let that dissuade you. It is not flaming at all and there is a super good vibe there! One thing that is interesing is that the outdoor cafe chairs are oriented towards the street so you can people watch on the Paseo.
Ask of you have any questions.