Trip to Sitges
Barcelona itself has loads of attractions and sights to offer BUT also the surrounding area is absolutely well worth seeing it. So, if you are staying in Barcelona over a longer period in a comfortable Barcelona apartment, you should definitely take your time to explore it.
My tip is - among others- to make an excursion to Sitges (with the Renfe train from Sants Estacio). The charming coastal city is located only 40km away from Barcelona and belongs to one of the most famous and attractive destination for people who are spending their holidays at the Costa Dorada.
Kilometer-long sand-beaches invite its' guests to swim in the turquoise-blue sea. The international gay-scene, which annually meets in the gay-friendly city Sitges, assures to place emphasis amongst the tourist-hypes. A walk through the picturesque, Mediterranean old town or along the beautiful boardwalk ensures you the feeling of "pure holiday".
When strolling along the beach, the small baroque church "Sant Bartolomeu I Santa Tecla", also called "La Punta" (the tongue) is immediately catching one's eye, not least for its amazing location: It is directly bordered to the sea. Numerous (fish-) restaurants, bars and café's invite its' guests to allay their hunger or thirst...of course including sea-view!
You could also conversely visit Barcelona from your holiday accommodation in Sitges. 
For instance, the Sitges apartment "Sitges Apartment Sea View" literally invites you to enjoy a really relaxing Spain holiday in the small but lovely city Sitges. The well-equipped Sitges holiday apartment offers a sleeping capacity of up to 4 persons and besides the community garden it offers a swimming-pool as well as a balcony with sea-view. What more would you want?
You are generally a Spain fan?
Then you should also visit the following blogs:
Coasts in Spain - Blog
Ibiza & Majorca - Blog