Defining what I consider a 'good book.' When I wrote The Tour Life (no longer posted), I would continuously add and remove description because of the different critiques I received. I had SO MANY critics with conflicting opinions I had no idea what I was doing. I wish I'd figured out I hate long descriptions and just settled for what I do like, which is getting to the point.

Not worrying about being the most original author to grace the world. I adore cliches. I honestly don't think you can be original when you're inspired by things that have come before. Now I write the books that interest me. If it's a cliche student / teacher romance, then so be it! At the end of the day, I'm the one who spent 17 months of my life writing it.

Chop the dialogue tags. I don't need them on every single line. To add, writing 'said' isn't invisible to the reader.

Show vs telling. My writing jumped so many levels when I realised I spent a lot of the time just explaining things. If someone is the characters best friend, show it through their interactions. If someone is afraid, describe how they feel. Showing creates realistic work.

Not to worry about the first draft. You need to have a book to edit. So just write.