If you have a subscription then Cancel it right away. F2p is alot less tempting and that's what I usually do like a month before finals and other important times. You'll miss it for like half a day, then you'll forget about it all. This same thing happened to me, and ending my subscription got me back on the right path. It's silly to think that you will be able to stop yourself from playing games completely. What's important is that you plan out your time. Finish all your work with at least 1 hour at night for computer / Xbox or whatever.
If you aren't a member, all I can suggest is take a break for a month, without logging in for any reason whatsoever.
5 X Dragon Axe.......1 X D Skirt...............1 X Bandos Platebody
3 X Zerker Ring.......1 X Bandos Hilt
4 X Warrior Ring......1 X Bandos Tassets