Haven't read thread but heres a couple of rules to follow
Don't do anything your not comfortable with
If you're going to play scenes where your beating her then everything should be negotiated in full before any play begins. Even if she wants scene to change halfway thru if it hasn't been negotiated don't do it
Safewords are a must. Traffic light "amber" if she needs a pause "red" for full stop works well
Always always honour safe words
Don't make first scene a full on one you need to ease in just as much as she does
Aftercare is very important as rough as she might like to play, a soft cuddle afterwards is just as important
Have fun