Books on how to write better are total cr*p. They're the same as books on being a better swimmer or better martial artist. In the end you have to DO it and THAT'S how you get better. Book knowledge has it's place and is a necessary starting point but most of what you read will be contradictory- just like diet books.
I think that the PR book will help you alot in becoming a better writer for Oh, only about 1000 reasons starting with - it will free up alot of your time and enable you to actually read alot of things you didn't have time to read before. The 2 best things about the PR book aren't even in the course- Syntopic Reading and Direct Learning. The way I found out that most writing books are total garbage is I went out and read them all. Go and do it.
Syntopically read "how to" books and DIrect learn motivational inspirational books and other than that, just actually WRITE the rest of the day. I can't think of anything else to do to help writing.