Our instructor in most of our Technical Communication courses told us that there is no good writing, only good rewriting. It is true that when we write we are very prone to make mistakes because we share our thoughts, and we open it for other people's criticism.
I know it feels scary because I really don't know how people would take my writing. I can't also control the way people would criticize my writing, so I usually just expect harsh comments. However, I also learned that I shouldn't really be scared to write because the more I practice, the more I will know what my mistakes are. It is normal to feel bad sometimes, but we shouldn't just end there. We should take each editing session or activity as an opportunity to learn and correct our mistakes. We shouldn't just correct the mistakes and comments in order to satisfy the reader or editor for that one piece of writing. We should understand the comments and corrections, and apply it to our next writing.
Practice may not make us perfect, but at least it will make us better.