All the bases covered so far.
Watching out for pickpockets: Check
Street photography also good Las Ramblas is excellent for it, plenty of interesting side streets, also very nice around the Ronda del Litoral for doing coastal shots.
Note Las Ramblas turns into a bit of a red light area late at night, so keep it (your film of course) in your pocket
Eats, plenty of Tapas bars about. Good value, pick and mix.
A well worth visit
"Flatter Me, and I May Not Believe You. Criticize Me, and I May Not like You. Ignore Me, and I May Not Forgive You. Encourage Me, and I Will Not Forget You."
Oh, thinking of Las Ramblas, as a general rule avoid the restaurants there. They're quite pedestrian and touristy and serve mediocre food at relatively high prices. Do take a wander through the Mercado San Jose though- LOTS of sights and potential for photography, as well as delights for the taste buds.