Well, since you opened that can of worms, I will attempt to opine.
Engineers, like everyone that serves, have to to be of service. Service to your customer, service to your discipline, service to your co-workers and so on. Like the old TV series in the U.S. says on its opening "Like sands through the hourglass, so are the days of our lives" and so are the ways in which we can serve.
The first service is to yourself:
Be true to your own principles and discipline in such a way that allows you to help others, such as the way the airlines say, when the oxygen masks drop, put yours on first, then help others.
The second service is to your fellow workers:
If you see a fellow worker who is having trouble getting on track, stop and help in a kind way. Show them the way and then get out of their way.
The third service is to your customer:
Make sure your customer is getting the best service and product that you can possibly muster. Think of the product not as your own, but view the product the way the customer envisions. Try to see the customer's POV and then think of it as fulfilling a dying wish, with all of the fervor and expertise that you can muster. Again, help your fellow workers see this ideal as well.
The fourth service is to upper management:
The budget is usually the driving force from management, so try to give 1-3 your best effort to keep the budget and mandate in check. There are times when management needs to bend some as a reality check, since quite often management looses sight of reality. It is your responsibility to oppose management on occasion in order to give them the reality check that they need. Many often think that pleasing management is the prime directive, however, nothing is farther from the truth. Often courage is needed in order to accomplish this feat, as well as support of your peers. Just realize that management is, more often than not, singleminded and one-dimensioned in their pursuit of budget and schedule. Another mistake that young engineers make is that management is the customer. Always keep the real customer in the forefront. Bottom line is that, although budget is incredibly important and should be factored in, it is not the most important factor. Projects should be evaluated by mature management of the project by seasoned leaders that can juggle all of the important factors and end up with a satisfied customer, within budget and on time.
I could go on, but the above are only a few guiding principles. You will make many decisions along the way and the best advice I can give is: Abide by your conscience and better judgement or you will have regrets. Use the knowledge that you gather and apply to future decisions/projects. Always bow to your gut feelings and give a nod to your instincts. Do not let external pressures cloud your optimal judgement.
That is all...