I'm not sure resurrecting this thread was the brightest idea, but oh well...
If you are riding as a student, I'm assuming that there are regulations in place about what exactly you can do. Some organizations might require you to wear a vest or something that clearly identifies you as an OBSERVER, some might let you carry bags, maybe you're even allowed to practice (under the supervision of someone with a card) skills you've learned in class. First and foremost know the actual rules. Then, talk with the crew you're riding with. Make sure you and they understand what is expected of you. Some medics/EMTs will be more willing to 'teach' than others.
My very first ridealong call ever when I was a student was a minor MVA. I thought that I would stand nearby and watch how a 'real' EMT interviewed and assessed the patient. Instead, I was handed a stat pad and told to get the hx and vitals. I wasn't expecting to be thrust into the spotlight at all, with troopers and other FD standing by with not much to do, so I was shaking like a leaf in a hurricane. (The pt didn't even have whiplash, but she had a hx of hypertension so she wanted someone to take her BP before she drove home. after i got her vitals, she refused anymore assessment, care, or transport). This was a rather extreme case of me misunderstanding what was expected of me and not communicating with the crew prior to the run. Obviously if it had been a more serious case, I would have been in the background like I expected, but it would have calmed my nerves a lot if I had known going into it that I might be "lead".
So yeah, talk with the crew. Some will be strictly by-the-books, some will not be. I had one officer tell me when riding as Observer on the fire side that if he saw me put on "that stupid Observer helmet" that I would be "thrown from the engine en route". Let them know what you've covered in class so far, and if there is down time, have them go over stuff with you that isn't covered in class. Example - our class basically taught to the national standards, but Maryland (and Howard Co) have some differences. We don't use PASGs, but we do have AutoPulses and LifePaks on every ambo in the county. We never learned anything about those devices in class, and both are used pretty regularly (especially the lifepak).
And my experience is basically that I'm a whatever-I-don't-want-to-be-that-day cloud. If I need to talk to an officer about something or train on something or get something done around the station, the tones never, ever stop. If I come up with plenty of free time and am itching for a call, the only action we see is on the Tee-Vee.