Four nights in Barcelona.

I am planning a spring break in Barcelona. What are the do's and don'ts of this city?

Lots of pickpockets. So keep things concealed or hard to access.

Other than that I dunno. Its a very easy city to get around, lots to see and do. Great place for a weekend.

Must say of all the Spanish cities I've been to Barcelona was my least favourite. I didn't find it at all appealing. Thought it was noisy and a lot of graffiti. Nothing in comparison to Seville, Valencia, even Madrid is much nicer but you will still have a good time. Cathedral very nice and you must visit the Port area, some great restaurants. If you get a chance do visit Tarragona, about an hour away, beautiful small city.

have a look on line at the metro system,its very good,and cheaper than taxis

Have a look on Tripadvisor.com, you will find lots of info and recommendations there, I find it a very useful site. Enjoy the break.