Ok, I think we need to flesh out the dkp system a little bit.
These are, as always, just suggestions at the moment - so feel free to comment.
Being ready for the raid on time (standing outside Kara, fully repaired, with pots before the raid is scheduled to start) = +1 dkp.
Attending the raid having signed up on GC (must've signed up at least 1 hour before the raid starts) = +1 dkp.
Successful raid bonus = +3 dkp (given at the end of the 'required raid time', although I think 3 hours is more sensible than 2 hours which seems a bit short for a raid. I also think it should be less than the dkp given for downing a boss)
Downing a boss = +5 dkp
Downing a boss for the first ever time (guild first) = +7 dkp
Leaving the raid before the 'required raid time' (again I suggest 3 hours) = -5 dkp
Going afk while we're on a respawn timer = -1 dkp.
Being found to go afk without announcing it on /ra = -2 dkp.