Get a feel for the flow: This is pretty zen, but: spy on masters of chaos -- bartenders on busy nights where they're making 15 drinks at a time, sous chefs holding down the line in a frantic kitchen, even cops at a crowded intersection. Pair that with smelling when a food order’s ready and hearing “bourbon rocks” over “Bohemian Rhapsody”, and you’ll be the Baryshnikov of the Bartender Ballet. Minus the tights. Hopefully.
Be willing to barback: Many badass bartenders begin there, and once you’ve got that job, the call-up could come quickly. You won’t be wasting time: “You learn speed, bar flow, product knowledge, and precision from being a bar back. Let the things you learn at the bottom be the foundation for making it to the top.”
On a slow night, ask your local for a guest shift: Guest shifts are infinity times more instructive than serving drinks at home to friends, who’ll either uncritically say you’re great, or that you’re the worst. Use them to learn how the bar works, and how everyone works together. Ask too many questions, because you can’t ask too many questions.
Don’t treat your friends too well: They should be there to support you, not the other way around. Instead of charging them $7 for a $150 tab, give ‘em the same service you’d give any good customer.