Here are simple options to start working on your English, whether on your own or with a teacher or academy:
I've included Amazon links for the books I've found there in case you're thinking about buying a book. If you use these links, you'll get the same price (the lowest price I've found) but at the same time you'll be supporting my account. Thank you!
This material is useful both for general improvement and for preparing for English exams specifically. I've used them for almost 15 years, and they have always been a safe bet for effective preparation.
Although in my classes we usually take a very personalized approach depending on the student's preferences/needs, when they need to prepare for an exam or want a general overview of the language that covers all areas, this is my choice.
If the student makes the effort and the teacher is there to provide support and corrections, it cannot go wrong.
<aside> 💂
</aside>
If you're just starting now and don't know where to begin, this is your book: Essential Grammar in Use - Spanish Edition
It contains explanations in Spanish so you can understand everything from the beginning.
The "Grammar in Use" series is one of the most practical books for learning English. Simple and straight to the point.
If this book seems too easy for you, but you want a practical solution, there are two more levels:
Course Book - Objective Preliminary (PET or B1) (You can buy it on Amazon here)