Not setting fire to your trailer
Not shooting the load out of the back doors
Not driving through brick walls
Not dropping your trailer on its knees repeatedly
etc 
I like to think am a good driver by taking pride in my work and doing the best i can but sometime i wonder if my boss thinks am a good driver or not by questioning me on why i didnt get that extra load done or why i went the way that i did 
… that just pee’s me off and then i feel like hanging it out so maybe am not a good driver who knows 
Initiative, taking pride in your job and appearance, good work ethic. Mechanical aptitude can help as well.
But the most important trait - COMMON SENSE.
Not setting fire to your trailer
Not shooting the load out of the back doors
Not driving through brick walls
Not dropping your trailer on its knees repeatedly
etc
he he he , nice one Semtex
My old man gave me one piece of advice when I passed my car test (many moons ago).
“Treat everyone on the road as a complete and utter brainless numpty and you’ll not go far wrong”
It’s worked so far.
Stan