Learn to plan and estimate.  That is something you can only learn at your particular place of work.  Both the estimating and the planning depend heavily on the type of engineering you do, the products your company makes, the needs of your customers, and how your company organizes itself.  Few engineers plan their work or estimate their time or the time of others.  It is the bigger picture.  It sets priorities.  It tells you if what you are doing is really important.  Even if you do not supervise the work of others, it helps you fit your work into the flow of work needed from all parties involved.

Don’t trust everything you were taught in college.  Textbooks are an endless source of errors.  handbooks also contain errors.  And not just a few.  And not just small errors.  Many years ago, (OK, eons ago) when desktop computers were first coming into the work environment, I was asked to check on a particular handbook that was frequently used by our engineers.  A new edition had come out, and it was supposed to be set up especially for use with computers.  So, I called the professor whose name was listed as one of the authors (the prime author had died).  We had a nice chat.  He said the the publisher was working with a programmer to write the software that would allow the new edition’s formulations to be applied to desktop computers. He also mentioned that the revisions to the new edition had brought with it a number of errors, and he asked if I would like a copy of the errata.  I said yes, and in about a week I received a listing of over seventy significant errors, some by as much as a factor of Pi.  Subsequent to that, one of our engineers found three more large errors.  The book’s subject was stress analysis!  In fact, it was the premier book on the subject, used by practically anyone who did stress analysis.

I have other examples of source errors, but you get the picture.

Given the time to think about it more deeply, I am sure I could list any number of things that you only learn on the job.  In fact, if you aren’t constantly learning on the job, the job gets sort of boring.