Let's see, your experience may be of benefit at the component level; system level - not so much. As for a list of what not to do...
Do not assume you are the smartest one in the room, it is likely that you are not, so don't assume it.
Do not expect to be recognized as special, you have to earn respect.
Do NOT treat any of the fully qualified Operators as dummies (even if they are annoying), you will alienate yourself.
Do not join in the bantering that qualified operators are having, see above for results
If they give you a nickname, do not fight it... That is the surest way to have it stick.
Do your best to avoid talking behind your classmates back or talking about other operators, word gets around and you will alienate yourself.
Do not be lax in your studying or plant walk downs - demonstrate mastery of the subject by both book and plant "smarts" to do this you must get out in the field as much as possible.
When qualifying, your qual book is not just a list of things to do, if there is something the operators are doing then get out and see it - help if you can... Even if you already have that "sig". Operators respect those willing to help and you will qualify faster.
Most of this advice is similar to life in the Navy, but it is worth repeating for you and for those who read this without that background.
XF
Edit:
Oh yeah, if the plant is union, try not to get too militant - especially if you might want to move up to SRO level at some point.