Curate, connect, and discover
Head canon accepted, it is now canon in my eyes.
He probably learned how to pickpocket from older orphans. Nothing like an unassuming small child to lower a person's guard.
He had to learn to resist the urge (or ger more creative) in Slytherin because if anything went missing, he'd be the first suspect.
Tom also curses like a sailor whenever his control slips & his sticky fingers never quite go away
Peep snakefaced Voldemort slipping a wall ornament from Malfory Manor into his robe when nobody but Nagini's watching