Our favorite Catalan food place to eat was called Atica in Sants (suggested by a local, def no tourists). They'll translate the menu for you, it's only in Catalan. Try the little neighborhood bar across the street for a drink or two . Mirablau for the view, La Boqueria (a must), and Elisabets for the local food were highlights too.
More about Barcelona in general - buy good walking shoes! the public transportation is AWESOME. My husband and I bought the 10 trip pass from a station kiosk to share between us. The train wait for any train is no more than 4 minutes.
We stayed at Barcelo Raval...great location, nice hotel. Yes you'll maybe pass by "ladies of the night" taking the short cut through the back alley but I promise we never felt unsafe.
We did a Best of Barcelona incl. Skip the Line @ Sagrada Familia 1/2 day tour. The skip the line alone was WORTH IT, the line was at least 2 hours long! Stop by Maria del Mar as a comparison. I'm not a very religious person but that place felt like a real house of God to me.
We went to Camp Nou for a Barca game.Yes, fans are die hard and make it fun. Trains get PACKED.
For a day trip I chose Tossa de Mar 1.20 min. up the coast. From the Nord station we bought bus tickets from the Sarfa window (2nd floor). The whole experience was what we hoped for. We ate at Bahia restaurant right on the beach. The food was delicious and sangria was awesome! A definite highlight!
Overall, I hope you enjoy this city as much as we did!