I loved being a student.
Here is some hindsight 5 years after graduating:
I should have:
1. Developed my programming/software skills. Specifically, MATLAB, Python, AutoCAD, VBA, and SolidWorks.
2. Made it a priority to meet people outside of engineering. Universities are the most convenient spots to meet MANY talented people (biz, law, humanities, etc).
3. Prioritized my health! Sure, your GPA is important, but value your health and happiness over an extra 0.3 ;). You are more than your GPA.
4. Worked on soft skills, especially public speaking and sales.
5. Took classes outside of engineering – especially business!
6. Started entrepreneurial activities early! There are SO MANY resources on campus now, from non-dilutive funding to legal guidance.
7. Been more confident in my technical abilities, and more actively pursued the things I REALLY wanted.
8. Took time to develop my interests outside of school vs. resume building.
9. Learned personal finance (retirement, taxes, loan repayment, credit cards, and budgeting).
10. Studied and aced the GRE. The GRE works for both grad and b-school, and scores are good for 5 years. For the engineers, also take the FE Exam.