Undoubtedly, the best way to learn a language (regardless of your level) is by immersion. In other words, moving to the place where the language is spoken natively and there, with the help of a language school, broaden your knowledge, both in culture and in the country´s language.
This is well known by the promoters of Babylon Idiomas, and that´s why they have schools open to learn Spanish in various points of Hispanic geography (Seville, Madrid, Barcelona…) and also in cities the other side of the Atlantic, where they also speak in Cervantes´ language (especially Costa Rica and Argentina).
Although Babylon is a broad language school with exchanges with other countries, they´re specialized in Spanish for foreigners, whose classes are made by highly-qualified professionals (they don´t admit any CV that hasn´t got any Hispanic Philology studies).
Also, to help the lesser fortunate economies, they have good discount coupons. The best, if you want to improve your Spanish, is to book online one of the excellent apartments in Seville that are rented by seasons, sign up at Babylon and enjoy a long stay in this beautiful and unique city in Andalucía.