Here's the next rule for you: DO NOT TOP POST Seriously, posting inline is easier to write and read and makes your email more clear. You don't have to wrangle your words to make it clear what part of their email you're replying to. If you don't need to refer to anything they said, delete the whole email and just put in a couple of words alone. Stop top posting!
Bottom posting is a good way to be branded "that weirdo who can't follow standard procedure". In the business world, this old Japanese proverb applies: "The nail that sticks up gets hammered down."