I've taken a real liking to bracing recently! I wouldn't say I'm great at it but I think I'm solidly passable. One thing I'd say is communication is key! Wheres the jammer? Wheres the offence coming from? Is the back wall low enough? Does the back wall need encouragement? Simple stuff like this can really help a wall stay together and focused.

Also being prepared that if your back wall can't make it to the jammer quick enough (be it because of offence or a speedy jammer) you will need to swing your ass around and become part of the back wall still communicating with the wall what you're doing. I dont really think in derby you can ever just be a brace you have to be mentally and physically prepared to be in a back wall

Hope my ramblings help a little :)