Food and Drink
Meals are generally hearty and consist of 4 to 5 courses. Spanish cuisine is characterised by the use of olive oil and lots of garlic in the cooking. Along the coast, fish and seafood constitute the main courses, while in the hinterland, lamb, rabbit and other meat dishes are generally served. ”Tapas” (appetisers) are typically Spanish, served at all hours.
Lunch is served between 1:30 pm and 3:30 pm, dinner between 9 pm and 11 pm. Service is included, but it is common practice to leave a supplementary tip.
Shopping
Сlothes and shoes
Designer shops: Besides well-known mass brands which is known around the world (Zara, Mango, Bershka, Camper), Spain has many designer brands which are more hard to find outside Spain - and may be worth looking for if you shop for designer wear while travelling.
Department stores: El Corte Ingles - National chain that can be found in every city. In most cities, enjoys central location but resides in ugliest buildings. Has department for everything - but is not good enough for most purposes, except maybe for buying gourmet food and local specialities. Still very popular with uneducated shoppers.
Souvenirs
Apart from classical tourist souvenirs, try the Kukuxumusu t-shirts. It's a creative series of good-quality T-shirts which are both funny and on the topic of Spain as seen by tourists. Produces some custom series for regional specifics like San Fermin event.
Business hours
Most shops and public offices close from 1:30pm to 4:30pm or 5pm, excluding those located in large malls or belonging to big stores. If you plan to spend whole day in shopping, a closed shop should remind it's also time for your own lunch. And when you finish your lunch, some shops will be likely open again.
Source: Wikipedia.
Don't
Spaniards in general are very patriotic about both their country and/or the region in which they live. Avoid arguments about whether people from Catalonia or the Basque Country are Spaniards or not.
It is customary to kiss friends, family, and acquaintances on both cheeks upon seeing each other and saying goodbye. Male-to-male kisses of this sort are limited to family members - a firm handshake is expected instead.
Spaniards of all regions are keen to maintain physical contact while talking, such as putting a hand on your shoulder, patting your back, etc. These should be taken as signs of friendship.
During lunch or dinner, Spaniards do not begin eating until everyone is seated and ready to eat. Likewise, they do not leave the table until everyone is finished eating. Table manners are otherwise standard and informal.
When Spaniards receive a gift or are offered a drink or a meal, they usually refuse for a bit, so as not to seem greedy. This sometimes sparks arguments among especially reluctant people, but it is seen as polite. Remember to offer more than once (on the third try it must be fairly clear if they will accept it or not). On the other hand, if you are interested in the offer, politely smile and decline it, saying that you don't want to be a nuisance, etc. but relent and accept when they insist.
Appearing drunk in public is generally frowned upon.
In Spanish beaches it is okay for women to sunbathe topless. This practice is particularly common in touristic areas. Full nudity is only allowed in "clothing-optional" or nudist beaches.
Source: Wikitravel.
Tips
Visas
Spain is a member of the European Union and the Schengen Agreement, which governs its visa policies. No visa is required for citizens of other EU member states, and those of nations with whom the European Union has special treaties. There are no border controls between Spain and other Schengen Agreement nations, making travel less complicated.
Talk
Unsurprisingly, the offical and universal language used in Spain is Spanish (español, castellano), but it's more complicated than that, as it differs in pronunciation and other details. It is part of the Romance family of languages (which together with Portuguese, Italian, French, and Romanian constitutes one of the main branches of that family), and is more properly called Castilian (castellano). However, there are a number of languages — Catalan, Basque, Galician, Asturian, Valencian, Balear, etc — spoken in various parts of Spain. French is the most widely understood in the north-east of Spain, like Alquezar and Cap de Creus (at times even better than English), as majority of travelers there come from France. Locals will appreciate any attempts you do to speak their local language. For example, "Good morning" and "Thank you".
Money
Euro: Spain is part of the European Union and the Eurozone. EUR 500 banknotes are not accepted in many stores--always have alternative banknotes. If you wish to exchange money, you can do so at any bank (some may require that you have an account there before they will exchange your money), where you can also cash in your traveller's cheques. Currency exchanges, once a common sight, have all but disappeared since the introduction of the Euro. Again, international airports are an exception to this rule; other exception is touristic districts in the large cities (Barcelona, Madrid). Credit cards are well accepted.
Source: Wikipedia.
Driving
By car
The motorways are toll roads. The speed limit is 120 km/h on the motorways, 100 km/h on the fast lanes and 60 km/h in town. Seat belts are obligatory in the front and back of the vehicle. The alcohol limit is 0.8 pro mille.
By train
Renfe is the Spanish national rail carrier. Long-distance trains always get in time, but be aware that short-distance trains (called Cercanías) can bear long delays, from ten to twenty minutes, and especially in the Barcelona area. To be safe, always take the train before the one you need.
By bus
The easiest way to get around most parts of Spain is by bus. Most major routes are point to point, and very high frequency. There is a different operator for each route, but usually just one operator per route. At the bus station, each operator has its own wicket. The staff at any of them are usually happy to tell you who operates which route, however.