Take this as a Barcelona Travel Guide :D
Barri Gothic Area is the oldest part of Barcelona city, and you must visit in order to give your sweet memories about Barcelona. But in my opinion, Architecture 20th Century is the best part of Barcelona.
You also have to visit all the monuments which are relics of the famous architect in the 20th century, Antonio Gaudi; including the Parc Guell, Casa Miro, Casa Batlo, and the most famous is the cathedral unfinished Sagrada Famiglia.
Another monument you should visit is the Palau de la Musica, Maritime Museum, Picasso Museum, the Olympic Complex, and the best nightlife in the Olympic Village.
Suggestions:
I encourage you to visit Salou, where you can find magic in the Port Aventura theme park. We spent two nights at the resort is close to the park, and order it directly through the Internet.
When I tried booking through an agent it cost me 15% more expensive. Therefore, I order it myself because it's very easy.
You can get to your destination with ease because the resort and amusement park has a station that is located just 100 meters away.
Port Aventura probably not as big as Disneyland Paris, but I personally feel that this park has a distinct atmosphere of adventure does not have an amusement park in Paris.
Another goal that you need to go is beautiful Montserrat Mountains, a visit to the beautiful resort Stiges located on the waterfront.
You can also earn a very lucrative package because it includes transportation, museum entrance fee, and lunch at the Tourist Information Office.
Guidelines:
Besides buying a guide book (my friend has a variety of guide books are very informative), I suggest you to visit Barcelona Tourist Information Office website, and contact them to ask some guidebooks.
With a very low cost (probably less than 3 euros), they will send a very handy map and guide book that will certainly be helpful in planning your trip.
