Sorry if this is late, but I was a lorry driver and have recently started as a trainee driver. some of the personal developments are the driver CPC, any ADR courses or any professional driving accreditations. I also stated that during long drives, I like to imagine I'm on a driving test. This keeps my concentration levels up as well as my skills. Another thing I said (I'm blue light trained from a previous job) I liked to do, was Risk Triggered Commentry. As I'm driving I would observe any possible dangers (car pulling up to junction, kids playing by roadside ect) and call them out as I'm driving along.
These are all to do with personal development. You have to remember though, always have safety at the heart of most answers (where appropriate).
Anyway, hope this helps and good luck.