Have your fellow or respiratory therapist go over vent's and all the settings, have them go over why they made certain changes according to the ABG.
Remember that when you leave the ICU you will never again see nursing care as good, ie your trust level won't be as high and just because you order it doesn't mean it'll get done like it does in the unit.
Try to be aggressive with procedures, lines, intubations, etc because this is where you'll get most of them.
Ask for help always, you always have your resident, fellow, and even staff (at least at my program they were available mostly). Like someone said misery loves company.