Writing, a difficult task

This week, I had the first formal writing assignment of the year, the memo. I knew writing is not an easy process, but it was so much harder to write formally. I had to revise the memo several times, get it proofread by others, revise again, and repeat the process. Now I understand that it takes a lot longer time and more effort to write a good, concise paper.
Not only with the formal writing, but with the less formal writings for other classes, I struggled as well. I thought the writing was not a big deal for other classes because they were not an English class. But I ended up losing quite a bit of points on my writings, mostly due to simple errors such as misspelling and grammar mistakes. If I proofread my papers even once, I would have caught those mistakes.
Writing is different from speaking in the sense that the errors in the writing are seen as a more serious problem than the errors in the speaking because writings could have been revised before submitted. Also, writings can be kept permanently.
I will take all of my writings more seriously from now on. I will put more efforts in writing, I will proofread, and I will take my writing to a writing center or TA's for revision.