My Generalized Writing Process Broken Down

As I look back on my writing process...I notice a familiar pattern that isn't wholly correct and leaves much room for improvement. As I edit for content throughout, I lead myself to believe that further editing is not necessary. I often neglect this, and this is a reckless mistake that will eventually be noticed at some point in my career. Though I do not plan on being a professional writer per say, I would still like to be eloquent in my speech and in any papers I may choose to do. As a child I never saw myself as any sort of writer. In fact I was probably the worst at grammar and speech at any young ages if compared to my peers. My Uncle would try to correct, but we all knew that I was doomed for english and luckily accelerated in science and math. I had always thought I would be a mathmatician of some sort, and would at least only gain enough command of the english language to get myself by in day to day life. However, as I went through English AP classes in high school, my teachers basically forced and scared me into actual writing. The best of my class usually wound up with C's and we were left to be as grandiose as possible, though we hardly knew what the hell we were saying. After that and meshing into a normal English class senior year, I began to understand and comprehend proper writing and soon writing was an easy task. Essays written during class were astonishing and later this quick style perfected in me. College continued this and soon I felt good and confident in my essays. However good they may appear to be...a lot of times it all falls short and I know I could do better. Though some of my sentences may seem impressive, the overall content tends to lack. I now know that I need to improve how I argue points. Most of my analysis leaves little proof of my actual point, and ends up being strictly opinions. Likewise my thoughts get disjointed, which would normally be caught upon later thorough reviews and edits. I never hand my writing to my friends or people I know out of fear of pure criticism. Though I know I'm not in any way...unintelligent, I feel that maybe my friends would look down on my grammar or syntax. Or laugh at a small mistake. But I shouldn't be afraid of a little criticism, if in the end it does help my writing abilities. I feel that for any essay I write, I should have my peers read it and comment for me. Any help...well helps. Likewise I should do my essays and other projects earlier so that I can eventually edit this myself with enough time to turn it in and such. These are the two key events that I must implement in order to better my writing.