Newbie Tips & Tricks

Hey y'all! I just started as a Barista last week and was immediately overwhelmed with the amount of buttons on the register and how it feels like everything is on fire during the morning rush lol. If you have ANY advice, whether it be about drink building (like how French Vanilla is actually Hazelnut syrup + Vanilla syrup), best shoes you've found, if it's worth it to buy from the employee merch site, how to handle super complicated orders & customers, or even how you navigated your training (and memorized the espresso & syrup ratios), please share! I'd be super grateful. I've worked tons of customer service based jobs, but never food/drink service.