By far the most important factor is how much time you are immersed in the language. The more time you spend with the language, the faster you will learn. This means listening, reading, writing, speaking, and studying words and phrases. This does not mean sitting in class looking out the window, nor listening to other students who do not speak well, nor getting explanations in your own language about how the language works. This means spending time enjoyably connected to the language you are learning.
Exercise your brain!
