What lessons have you learned over the years as a TENURED FULL Professor that you wish somebody had told you when you started as an Assistant Prof? As a Tenured Full Professor and given your long experience in Academia, what valuable lessons have you learned over the years that you wish somebody had shared with you earlier when you started as an Assistant Professor? Given these experiences what would you do differently if you had the chance?
You do not have to accept responsibility without appropriate authority.
It's a classic problem in any organization, and it's related to Dave Clarke's answer. Some concrete examples:

Rather than extend the deadline for homework when the bookstore doesn't have enough copies of the course textbook, give the students the email of the manager of the bookstore so they can write him directly about their situation.
Rather than ask meekly for a bigger classroom when there aren't enough seats for the 47 students enrolled in your class, give the email of the department coordinator who's responsible for assigning classrooms and say this is the person to whom you should vent your unhappiness.
Rather than teach a course that is watered down because it has no prerequisites, teach to the higher level students and explain clearly in the syllabus what you expect people to know. If students complain, explain to them your predicament (if you teach the basics, half the class will feel they wasted their experience). Students have more power to change an academic program by organized, constructive complaining than a non-tenured professor.
If the department chair doesn't involve you in selecting TAs for the course you are responsible for, and students are not happy about the quality of the TA (or the TA hounds you for a lot of help because he wasn't qualified to teach the course), encourage the chair to allow you to be involved in the selection process (refer to the principle of authority and responsibility).
If you're asked to be on a committee, insist that the committee have a clear mission that's feasible within the authority of its members. If a mission cannot be clarified or you can't identify with the mission, then minimize the amount of time/energy you put into it.