You can play the B/F# in a couple of different ways. This way is how it sounds like he
it in the song:
B : 221xxx
But, if you feel like adding in a nice note (a bit tricky though), play it this way:
B :2214xx
and use your pinky for the last note.

If neither of those suite you, you can always play it this way:
B : 2244xx

Just make sure not to hit all those high notes, as the "proper way" to play the chord
be... at least not in the acoustic-guitar verses, because it's only the bass notes played
the song.

Lastly, in terms of ending the choruses with the E major to E minor switch, you can play
chord to the next, or, to sound more like the song, you can strum the individual notes
this:
E-------------------------------- | 
B----------0------------0-------- | 
G--------1---1--------0---0------ | 
D------2------------2------------ | 
A-------------------------------- | 
E-------------------------------- | 
       E major      E minor


Enjoy...


B                       E
Keep a little organ in you, now.
B                       E
Sing about the promises you found.
B                                 E
Keep it up, ?cause no one likes it down.
F#                     B
Get lost in the overrated down.

B                       E
Keep a little organ in you, now.
B                                   E
Sing the song that filled your mother?s house.
B                             E
Little Thomas, he just wants to doubt.
F#                          B
So sing a song you never sing aloud.

Chorus:

Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be the last one standing out?
Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be filling up the dark?
Abm        F#   C#m
Oh yeah, yeah yeah.
            E            Em
So just sing it loud, once you think you?ve figured out?

B                 E
How you grew up so fast,
B                       E
Hoping to the face inside the glass.
B                                    E
You kept the beat, but you always came in last.
F#                                     B
And I?m the kiss, you?ve been keeping secret stashed.

Chorus:

Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be the last one standing out?
Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be filling up the dark?
Abm        F#   C#m
Oh yeah, yeah yeah.
            E            Em
So just sing it loud, What I?ve never figured out.


*Guitar Solo*


Chorus:

Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be the last one standing out?
Abm       E      B
Oh yeah, yeah, yeah.
B
Don?t you wanna be filling up the dark?
Abm        F#   C#m
Oh yeah, yeah yeah.
            E            Em
So just sing it loud, What I?ve never figured out.


B                       E
Keep a little organ in you, now.
B                       E
Sing about the promises you found.
B                                 E
Keep it up, ?cause no one likes it down.
B                       E
Keep a little organ in you, now.
B                       E
Keep a little organ in you, now. (Continue and fade until end)