Be sure to have dinner at Los Caracoles- it's well over 150 years old and was wopnderful when I had a magical dinner there, well over 50 years ago. It must have slipped somewhat since, judjing by the Yelp reviews, but you should definitely try it.
I recommend the snails.
My dad was their last year, and he said the food there was great! I wouldn't mind traveling to Barcelona myself in the future. Any recommendation you'd like to share? I assume you've made your trip already.
Been to Barcelona a few times, and although I didn't enjoy the food that much the city is surely very amazing. Of course, try Paella with rabbit meat and as many tapas as you can. They have quite fantastic paella made with squid-ink, I like that a lot. Can't really recommend and exact place at all, try not to eat at touristic spots like Las Ramblas etc. Generally speaking, you should be rolling just fine with Tripadvisor. Have fun!