Teach them to be unapologetically assertive. I don't mean be a bully. I mean to confidently hug the center line for making a wide right hand turn.. Signaling well in advance and make a clean swift lane change.
Teach them to use the amount of road they need.
Make them understand that every driver behind them hates their guts,just for being in the way,and to be prepared to avoid or defend.
Teach them that other drivers will tailgate and can't be seen in the mirrors. Depending on the conditions you can use shadows to tell if anyone is behind you. Teach them to keep a good eye on the mirror for trucks overtaking them and to get a firm grip on the wheel. Most trucks are non events, but every once in a while a particular truck will suck/push like a mofo. Not good for it to be a surprise!