The answers to these questions tend to be very unit-specific. As a new grad, you should ONLY work on a unit with great, supportive team members. I would say that is the number 1 thing to look for when you interview. There is no quicker way to sink when you're new in ICU then working with nurses who are not 100% on your side and looking out for you. No if's, and's, or but's about it.
As for the rest, sometimes there are aides and sometimes not. 99% of time on my unit, there is no aide, we do it ourselves, but we do have an awesome team that will help you whenever they can. In the last year, I can only think of 1 or 2 instances where I needed immediate help and had to manage on my own, and that was only because there were multiple other patients crashing all at the same time. Even still, we made it work.
No one can teach you have to prioritize; you have to learn it yourself, and it really depends on the patient's situation. ICU nurses tend to be picky about things looking neat and clean, but when you're patient's losing their airway or their blood pressure, it doesn't matter that their pajamas are from yesterday and the bed linens haven't been changed. Be prepared to make a plan, then change it immediately. But make the plan anyway, because occasionally things go the way you expect! :) (And it's very exciting when that happens...a cause for celebration, really!) Also in terms of prioritizing, learn to think of yourself, too. YOU are a priority. Your charting is a priority, for example, so that you can go home on time. Fit it into your day. MAKE time for the things YOU need to do to get your job done and done well.
And as for time management, you have to learn that one for yourself, too. I think a lot of the pressure on new grads is self-imposed. (At least it was for me.) Remember: this is a 24 hour job and it IS okay to pass things on to the next shift, even if they whine. You simply cannot do it all in 12 hours, end of story. Of course, people will sniff you out quickly if you are being lazy. :) Technical skills like IV starts, suctioning, etc, will be slow at first, but soon you will be amazed at how quickly you can accomplish these things. It just takes time and patience with yourself.