Some major mistakes that most of the students make in their Graduation days that I find quite repenting are:
Studying for just marks: The topper is studying just to score maximum marks. The average student is scoring to get above 65% marks. Some below average students are studying to score the passing marks. Every one is studying just to score marks. According to the potential but no one is willing to acquire the practical knowledge of the subject.
Studying a day before examination: Most of the students prefer this notion of “One night fight”. Your parent’s have spent huge amount of their hard earned money just to see you becoming an engineer. So it should be up to you what type of engineer do you want to be? A one night engineer or a engineer who studied every night?
Unbalanced Life Style: I often find most of the engineering students living an unbalanced lifestyle. No proper sleeping routines, not following proper hygiene, excessive drinking and smoking etc. These are all signs of an unbalanced lifestyle.
Having no idea about the future: Most of the students in B.tech have no clear cut idea about the future. You should be clear about your goals in your first year itself. If you have no aspirations of becoming an engineer. Then it is best to leave the engineering in the first year itself. If you want to crack some government examinations then it is best to get a regular B.A or B.Sc degree. As it will save both time and money.
Not indulging in extracurricular activities: Your soft skills matters. To improve your soft skills you’ll have to interact with people and listen to them. Extracurricular activities helps you in honing your soft skills. I found most of the students not interested in the extracurricular activities and believe me you’ll be lagging way behind of the students that were good in their soft skills.