Practicing English by watching films is good for improving your stamina, but there are other things you can do as well. Take a film that you know very well from watching it in your mother tongue. Now watch this movie in English (with English subtitles if you like) and you will learn all kinds of language because you know what they will say so you can pay attention to how they say it.
When you’re watching a film for the first time, after a conversation you understand that he’s mad at her, she wants a divorce, there’s not enough money… the basics. When you watch a film that you know, you know what will happen–he’s going to tell his mother-in-law that he hates her and then she’s going to tell him that she’s going to ruin his life (I’m afraid I’m not very good at writing movie scripts)–so you can really pay attention to how he tells his mother-in-law that he hates her and how she says she will ruin his life. You’ll be able to remember much more vocabulary this way and learn lots of new and exciting ways to express yourself!