English is not my first language either, and at first I was very self-conscious when writing or generally communicating in English. What at first helped me to become more natural in using the language was watching a lot of TV (if Netflix is available where you live, then it's a great option; or just youtube or dtube videos made by native english speakers) and reading books in english. At first, I needed to use dictionary a lot, then less and now I am OK without. Of course, moving to English speaking country and using the language in everyday life is what ultimately made me confident in communicating and expressing my ideas, but if you don't have that option (or just plainly don't want to), reading and listening a lot is helpful, as well as communicating with others online (like here, for example). :)