There are many different English Language Schools to choose from all over the world. The school you select will be a trade-off between location, cost and reputation. English language schools vary a lot with class sizes, study times and supporting languages.
There are a few alternatives to going to a school to learn English. You can study from home although unless you are very dedicated and have access to a native English speaking person you may find this very difficult. There are plenty of online course that can help you to learn English. Online courses can be quite limited as it's up to you to find the answers to your questions which means that learning English can sometimes be quite a frustrating process.
We've found that private one-on-one English tutoring is the most effective way to learn English. You could use a private English tutor exclusively or in addition to studying at an English Language school so they can help you with the areas you are struggling with or go over more advanced topics that aren't covered in the course (such as Business English).