There is so much to see and do in Barcelona. With so much to do and so many memories that you will have you will wan to do everything that you can to record and preserve them. Starting with all of the museums that there are to visit to the great architectural works of Gaudi, you will not be bored and will definitely need something to help spark those memories when you look back on them. So make sure that you have a high quality digital or film camera and even a video camera or recorder of some sort to be able to have these memories to share and pass on.
When you are planning your trip make sure that you take into account the weather as it can also be a hindrance in Spain. If it is a rainy day, plan on visiting many of the indoor attractions that are offered and available. From the multitude of shops to all of the historically significant sites the options almost seem limitless. This is also a very viable option as there is always the possibility of it being to o unbearably hot to be able to enjoy the outside.
When considering planning a day on the outside do not forget to visit the Sagrada Familia, the famous Gaudi designed church, as a starting point. You will also want to look at many of the other monuments and structures located throughout the city and surrounding areas. Some of these are Guell Park as well as the Christopher Columbus monument to name a few of the landmark sites.
Other outdoor suggestions would be to make a day of Costa Brava and just spend the day combing and exploring the beach and the vast coastlines that the area has to offer. This is a very clean and well kept area that is always inviting on a nice summer day. If you are a sports fan you can always look into taking a soccer match for the home team. This would be something you would have to plan in advance for as there season runs from September through March and usually the tickets are hard to acquire.
Just do not forget to take your camera as there are so many interesting things to do and see on your vacation that nor only will you not wan to forget a minute of it, but you will want to have something to look back on while doing so and sharing your memories.