Well, I'm actually dyslexic, so my spelling and grammar was, well, suffice it to say flawed before I came across the internet. When I started going onto forums, using word documents and joining RP circles, I got a lot more practice with writing than I'd ever had before, and I was able to read well-written posts and learn from them. Also, I guess as I was more exposed to the internet, I got a sense for post-structure that bothered me, and developed a sense of what was and wasn't a good paragraph. It was the best place for me to practice and overcome my dyslexia.