The great advantage of military service is that unless you're an airman recruit about to get off the bus on the first day of Rookies, you're almost always in charge of someone. A Corporal points an open palm at a bewildered and pimply recruit and barks 'You! Yes, YOU! Get these people into three orderly ranks. NOW!' Instant leadership practice with compliant followers and immediate 'feedback' yelled in response to every mistake.
(It's not really Leadership of course, any more than a police officer's charisma leads you to breathe into her breathalyser. But it's Leadership with its L Plates on.)
In the military, your teachers call you 'Sir'. The really good ones patiently and generously allow you to 'lead' them, when really they are shaping and educating you. Luckily for me I have been taught by some of the best.