This is a very basic transcription of the piano part played throughout the song to be
on finger-picked guitar (in fact I think it's played very quietly in the background on the record)
Tuning works best if it's Dropped D and with a capo on third fret so
e
B
G
D CAPO ON 3rd
A
D
Let the bass note ring
|0-------0-------0-------0-------|
|--0-------0-------0-------0-----|
|----0-------0-------0-------0---|
|--------------------------------|
|--------------------------------|
|2-------2-------2-------2-------|
[ Tab from: http://www.guitaretab.com/s/snow-patrol/187595.html ]
|0-------0-------0-------0-------|
|--0-------0-------0-------0-----|
|----0-------0-------0-------0---|
|--------------------------------|
|--------------------------------|
|0-------0-------0-------0-------|
|0-------0-------0-------0-------|
|--0-------0-------0-------0-----|
|----0-------0-------0-------0---|
|--------------------------------|
|4-------4-------4-------4-------|
|--------------------------------|
|0-------0-------0-------0-------|
|--0-------0-------0-------0-----|
|----0-------0-------0-------0---|
|--------------------------------|
|0-------0-------0-------0-------|
|--------------------------------|
Repeats for entire song.
The "hook" is played like this (Capo 3rd still)
|7---3---5---0---|
|----------------|
|----------------|
|----------------|
|----------------|
|----------------|
Pretty much all there is to it acoustically.