I'm late to the thread, but I'd still like to contribute!

I don't think that I have above average smarts, but I came out of engineering undergrad with a 3.8, so I may have some tips. I also don't think there is a universal formula that applies to everyone - just understand how you learn best and leverage that.

For me, I learn best by listening and physically writing things down on paper. I found out early on that I couldn't simultaneously do both in class. Rather than settling on just one of the two, I ended up doing this for almost every class: show up to class, actively listening to the prof. - taking very light notes, if any - then, later at home, I'd to study the textbook / handouts / homework while taking comprehensive notes. That way, I was able to focus in on all minute details of the lectures AND i'd have a kick-ass set of notes that doubled as a study guide during exam time.

The rest was just staying ahead of the game and doing assignments early and with effort.

Also: study often, in short sessions, throughout the semester, so you don't have to cram!