Read a lot. As an aspiring writer myself I know it is extremely important to be constantly reading. Practice and read all the time. It doesn't matter if English is your first, second or 50th language. Practice and dedication can and will make you completely fluent. Also, because English is your second language, your grammar will most likely be better. I recommend asking other authors (like myself) for assistance or trying to find some media with the things you struggle with. All in all, I wouldn't be too worried. As long as you stick to it, you will prevail. Good luck and cheers~
Mable