In order to become fluent in ASL, you will have to be invested in Deaf culture. Since deafness is rarely passed from parent to child, Deaf culture is one of the few cultures where a child does not learn the cultural traits from their parents. Instead, the culture evolves from deaf schools and community gatherings. Sign language is but one small aspect of Deaf culture.  In Deaf culture, deafness is not viewed as a disability that needs fixing. The terms "mute" and "dumb" are culturally insensitive, and should never be used. In general, individual Deaf communities are tight-knit and initially hard to break into. But persistence and a humble attitude will help you succeed in making deaf friends. Once they know you are sincere and eager to learn about them and their language, many deaf people will begin to accept you and "show you the ropes" of their unique culture. The Deaf culture is built on strong literary traditions, especially in poetry. You cannot learn ASL simply from reading a dictionary or watching some videos. Finding a partner to practice ASL with on a regular basis will be crucial for improving your readability, speed, and comprehension.  Post a bulletin at your school asking for an ASL partner. Get a friend or family member to learn ASL with you so you both have someone to practice with in everyday situations. The goal of learning ASL is being able to communicate fluently with someone who is deaf. Once you start feeling comfortable with basic sayings, go out of your way to interact with someone from the Deaf community.  Find out what Deaf community events are happening in your area, such as art shows, movie screenings, or gatherings. Go to a Deaf Coffee Chat. They are typically (though, not always) oriented towards beginners and you are likely to find Deaf people who are happy to chat with you. Be polite and ask if someone would like to engage in a basic conversation with you.

TL;DR in Indonesian:
Biasakan diri dengan budaya Tunarungu. Berlatihlah dengan partner. Berkomunikasilah dengan tunarungu.