The C's are played longer than the G's. And the D string is hammered on incessantly. From this video http://www.youtube.com/watch?v=dbtfnHg3Lwo
Have shown how I think the chords are played, but if you're not fussy I'd just play them 
GCAmEmC/GD e|---3-----3-----0------0-------0-------0----------|
B|---0----h1-----1------0-------1-------3----------| GCGC
GCGC You remind me, of cigarettes,
GCGC The way I hold you, in my chest,
GCGC The way you kiss me, with your filter breath,
GCGC And I keep thinking, I'm getting over this.
AmEmC/G Once you had me, you don't have me anymore,
AmEmC/GD I don't crave you in the morning, or at the company store,
AmEmC/G I don't use you to escape, in my fingers out the door,
AmEmC/G Once you had me, you don't have me anymore.
CGCG But honey you're smooooooooooth (x4)
GCGC You don't make me, coooool,
GCGC And I can carry on fine without you,
GCGC You're a spirit, and you can't be beat,
GCGC When I'm jonesin(?), honey I buy cheap.
AmEmC/G Once you had me, you don't have me anymore,
AmEmC/GD I don't crave you in the morning, or at the company store,
AmEmC/G I don't use you to escape, in my fingers out the door,
AmEmC/G Once you had me, you don't have me anymore.
CAmD Yeah but the truth is, that you do,
AmEmC/G Not the way you used to, but I keep coming back to you,
CGCG Because honey you're smoooooooth
CGCG Honey you're smooooooooth (x3)
CGC etc.