You can learn finance and accounting and media buying from a book. But the best way to truly learn how to do marketing is to market.3. I just finished reading Lev Grossman's The Magicians. Great book and I'd be reading the sequel right now if it was out. Like if Bret Easton Ellis was hired to write a new Narnia book. $6 at Amazon.
You don't have to quit your job and you don't need your boss's permission. There are plenty of ways to get started.
If you see a band you like coming to town, figure out how to promote them and sell some tickets (posters? google ads? PR?). Don't ask, just do it.
If you find a book you truly love, buy 30 and figure out how to sell them all (to strangers).
If you're 12, go door to door selling fresh fruit--and figure out what stories work and which don't.
Set up an online business. Get a candidate you believe in elected to the school board.
The best way to learn marketing is to do it.