Thanks a lot for that guide! 
I hope that many will contribute and add to it. In the past I have been asked a few times how to get started in RP or what that even is and how it works and to someone who never did it, it all must sound like a huge mystery.
Many things we just take as granted and assume that everyone knows, but I fear that’s not the truth! And having a little glossary and guide at hand is always nice!