I'm on track for a first overall providing nothing goes tits up this coming year. Was it hard to do? Not really, no. Did it require me to not waste most of my time as my peers did? Yes.
That said, don't get the impression that I've spent the last two years in the library and have never missed a single class. Some modules I've skipped around 35% of the lectures, kinda out of boredom as it's just as easy to read the powerpoints and do my own research where necessary. Last semester I went to the weekly practical session a grand total of once so I'm not exactly the 100%'er type.
All I made sure was that when it came around to coursework, I gave myself enough time (though hardly started the day they were set) and forced myself to work in my room or the library with no distractions for a few weeks. Pushed myself to learn some more complex CS stuff and ended up getting some of the highest grades overall on my course. My flatmates were going out a few times a week and procrastinating 75% of the time in comparison thus ended up with grades ranging from 30-60%. Luckily my course is mostly coursework based as it's CS, if I had exams then I'd probably have had to study more but the same principle holds.