This is something that a lot of writers do in the beginning before they decide to branch out. Before you know it, you'll be sharing with others, even though that time may seem like a long throw in time from now. I get that the language barrier is exactly that: a barrier. But we live and learn, yes? Of course it helps to have an underlying desire, a personal goal if you like, but with an objective at the end to look toward.
As others have said reading is essential but you will find that you have a real friend in English television and movies, too, and don't dismiss the local news broadcast. The point is, I think, to immerse yourself in the language that you want to write in and pay attention to how words are used and why they're used in the manner they are. The gist of a language is easier to understand than the subtleties but oftentimes watching a person speak and paying attention to body language, or facial expressions, will lead to a better understanding of word usage as well. All the trivial things that seem unimportant now will help you improve your understanding of the language and its usage.
Good luck.