Writing with proper grammar allows you to be understood. I recommend
Rex Barks for diagramming sentences. Practice diagramming and understand the rules of grammar consciously, rather than implicitly, so you can use them if you need them.
I recommend freewriting at the end of your day with the goal of reviewing what was good about that day. You will be able to write drafts better and will have the added benefits of positive thinking.
Freewriting - Wikipedia, the free encyclopedia