It's easy to master your Arabic language in a short time as many of my students have done , But you need to follow the next steps :
1 - Focus well on the lesson.
2 - You have to attend the classes on a regular basis.
3 - Review all what you study the class. ( Write down , repeat , memorize words, ...etc. )
4 - If you do not understand anything, ask the teacher, and the teacher will explain it to you over and over again.
5 - Choose the appropriate teacher for you, / must be a specialist in Arabic / and have a great experience in teaching / and also must has a clear voice / and the lessons should be run in a very calm environment.
6 - Also, Beware of people who speaks Arabic but they are not teachers, this will waste your time, and your money. ( Unless for exchanging language only ) .