Some people study Spanish out of textbooks, while others rely on lessons or special programs. All of those methods work, but none of them work as well as traveling to learn Spanish in Spain. A lot of the benefit comes from the power of immersion, but there are also lessons that can only come from exposure to another culture.
When it comes to languages, practice makes perfect, and there are many different types of practice. Memorizing vocabulary lists and constructing sentences will help you get better at those things, but Spanish is very different once you get out of the classroom. Real speech involves dealing with things that you don’t quite understand and composing sentences on the spot, and that sort of thing is impossible to practice in a class. Full immersion in Spanish society means that you get that kind of practice constantly, so there’s no better way to get good quickly.
Every language is part of a culture, and learning to speak that language involves learning about that culture. It’s possible to learn about etiquette and traditions from books, but that won’t teach you much about how people live their daily lives, and how people express their ideas. Visiting Spain and taking the time to experience Spanish culture will give a more complete picture of the culture.
Any exposure will help, but people who plan to learn Spanish in Spain will benefit the most from studying in place with a lot of different activities. Granada is one of the best options. It’s an ancient city, so it’s easy to learn about the history of Spain by looking at the relics of the past. It also has good weather for most of the year, so there are plenty of opportunities to learn about how Spanish people enjoy nature. Finally, it’s a reasonably cheap city, so seizing those learning opportunities is affordable and easy.
Any skill that isn’t practiced will fade, and languages are no exception. The best way stay sharp is speak Spanish regularly, but there are times when that isn’t an option. The next best thing is to make the learning process as memorable as possible. New experiences help form strong memories, which makes the learning process go faster and makes it harder to forget what you have learned.