Well, I'm an engineer too(Not stupid but I can tell you a few things to help you out). Firstly, You have to learn to compartmentalize your brain.
Anyways, the list:
1. ACADEMICS is always #1. Not sports, not women, not working out, not nothing. Become a hermit if you need to.
2. You obviously have core classes you need to do....most likely 3/term Concentrate on those as much as you possibly can. Get tutors(They are free in the US I believe inside the University for those classes) if you're having problems in your core classes. Always aim for a B or over in those classes. They are normally 4 credits each and have a major impact on your GPA.
3. For your electives. PICK EASY ONES. So that they will boost your overral GPA. A lot of people pick really hard ones and get overloaded with work, and end up with sub 2.5 GPA's for their troubles.
4. If you're having problems in your core classes attend the focus groups. Yes, I know they are gay, but they do help some people out in some of the course material.
5. Don't skip classes.
6. Try to get at least 7 hours sleep......seriously not a joke. I'm at least 3X more productive when i'm alert then when I'm dead tired from lack of sleep.
7. Eat clean....makes a huge difference for your state of mind. No fast food.
8. Work-out if you can...it doesn't have to be for 1+ hours. 30 minutes is enough with sufficient intensity. If you don't have time on weekdays, work out on weekends only. Working-out is 70% nutrition and 30% consistency. Remember that.
9. Don't FRIGGING DRINK. Yes, i know this is hard, but my capacity for multi-tasking and doing math and physics goes to shit for at least 2 days after I have a few drinks. Alcohol will make you dumber...yes it sounds corny but true.
10. If you want good grades, your social life will suffer......that's just a fact of life. Unless you're a genius you're going to have to hit the books hard, so no going to the bars on a daily basis. The good part, is that in the long run, you'll know who your real friends are.
Btw, I made the honor roll 3.25 GPA + doing Nuclear Physics, so I know what you're going through.
Engineering is one of the toughest and most demanding careers you can try. Over 40% don't get past the first year. So, if you did congratulations.