My Strengths and Weaknesses in Writing

I have been studying English since I was in middle school in Korea. For this reason, English was always part of my life. Actually, English has been a 2nd language in my country even now. It is important to get a high-level job, as well. That is why I choose to come here and study abroad in U.S to improve my English skills, and it certainly helped me to improve writing skills by studying abroad.
However, my strengths in writing are vocabularies. Of course, I am not perfectly fluent as native speakers, but I'm getting much better in this part since I came here. Actually , I have lived in U.S for about 2~3years when I was a little child. Even though my memories in U.S are unclear, because I was such a little child, that experience in U.S really helped me improving English than before and it was much easier to understand than other foreigners in ELI. I believe my ability of making vocabularies have been set at that time.
On the other hand, my weaknesses in writing are structures. I always get confused which grammer that I have to use in a certain sentence. When I came here to learn English, I got more confused because I had to learn in English and I couldn't understand few of vocabularies and had to find the dictionary and translate all the words quickly. However, that didn't really helped me to improve my grammer skills. For that reason, to improve my structure skills, I decided to just listen and pay attention what the teacher was trying to say in class, and I studied alone after class and I only asked questions that I really can't solve by myself. It seems simple, but it took a long time and patience to study. Now, I believe I am getting better than before because of this method that I tried.