Not sure if you'll ever see this, but it's good that you want to improve, and for this your are entirely forgiven. The only tips I can really give you are to be consistent, and try and be grammatically correct.

I don't care if you use e-mail or email, as long as you stick with the same term. I do care if you use lowercase "i"s when you should be using capital "I"s though.

That being said, everyone can improve, so just keep learning and writing. I have just bought the above book too. Everyone has space to learn. Good job on taking my criticism positively as well, even if I did sound a bit irked.