Honestly not really, just communicate with your trainer about what makes sense, what doesnt, and if you're confused on anything. Ultimately the trainer is there for you so ask anything you feel you need to ask. A lot of it will just come down to time, you'll get more and more comfortable every time you work

i’m really shy, too, but it really helped to observe the faster, polite, and knowledgeable baristas at my store while i was learning or felt inadequate in making small talk or knowing how to make something. they usually have a few questions up their sleeve to ask customers, like how’s your day, on your way to work?, what are you up to today?, or asking a simple question or comment on their drink like “this sounds tasty, my favorite is x!” i have a lot of trouble small talking with custies, but i try to imitate the nice baristas around me. if you act like youre confident and know what youre doing, it’ll appear that way to customers too :) you got this!!

be honest about what you need more help with. chances are that any real learning won't happen until your training is over so ask questions when you have them. also don't be afraid to talk to customers even if its just to ask how their day is going. I noticed that managers/shifts like to see that in partners since customer connections are really important to Starbucks.

good luck!