The best way to become fluent in Spanish is to immerse yourself completely in the language. Although living in a Spanish speaking country is the easiest way to do this, it's not the only way. Other than learning basic grammar from a book, you need to apply your skills by speaking Spanish as much as you can. If you don't use it, you lose it. Try ordering food in Spanish when you go to a Mexican restaurant. Find meetup groups in conversational Spanish. Ask the people you know who are bilingual to only speak and write to you in Spanish and don't let them switch back to English even if you don't understand at first. You need to be surrounded by the language in all forms, listening to it, reading it, writing it, and speaking it. Watch Spanish films, listen to Spanish music, and change your phone settings to Spanish. The fastest way to learn is by using the the language as much as you can. Don't be afraid to make mistakes and start by saying as many words and phrases that you already know. I hope this answer helps, as I have been through the language learning process myself to become bilingual. I am passionate about the Spanish language and am here to help anyone willing to learn!