Authors note or A/N- Simply, something the author would like the reader to know that is not part of the body of work.

I know, I know. It's very hard for people to write a story without putting their opinion in. 

I'm not saying you can't, I'm saying you shouldn't do it at the wrong time!

What not to do:

1. Don't randomly put an authors note in the middle of writing a story. It seems unprofessional and it can kill the mood. 

2. Don't make the A/N completely random. No body really cares about what you have to say unless it's about the story.

Remember:

If you want to write an A/N, at least do it at the end of the story! It would be a lot neater if you did that.