The best way to improve is to practice a lot. The more you do something the better you will become.To increase vocabulary you need to read a lot,or to listen to music and to watch movies.If you write and get corrections here, it is important to understand the mistakes that people correct.You should ask why if you don't understand something!

I have been learning Korean for two years, and to me, the best way to memorize vocabulary is to visualize it and study words that are relevant to you. Remember that language is a way of LABELING things. Every word we know can be associated with an image in our head or the things we see, smell, hear, etc. So when I learn a new word, I close my eyes and visualize it in my head while repeating the word. I write it down. I look up pictures and videos of it online. This makes my brain remember the word effortlessly because it has an image to associate it with. And try to learn words that matter to you and that you use a lot, or want to use in your daily life. As for improving writing, just write a lot! As kids, we all start out writing poorly, but the more and more we write, the better we get. Also read articles or books that interest you and write down some sentences and words that you see. Write about things that are important to you. I hope this helped!

write compositions regularly and get someone to correct them