All you need is Consistency
I always say that English is not that type of hard thing. Specially the writing part. If you dedicatedly practice for just 3 months, you will improve both in reading and writing. You will get good speed which is extremely important.
Writing consistently will help you to become a better writer. It is a great skill and ability when someone can write and express their views, ideas and opinions in their own language. That’s why you need to practice daily.
Start with commenting in the posts . Everyday we the members are creating hundreds of good posts. So you have lots of posts where you can comment without any hassle. Just stick with the commenting.
See the magic after 30 days. You will be able to write longer posts. It is proven and the success rate is 100%.