if you know what kind of music she's into, take a *simple* song she likes and show her how to play it. show her the chords involved and how to strum them. one of my 'students' has trouble with getting the strumming to sound natural.
try using a song to show her something new.
this way she's learning new stuff and has songs she can have fun playing around on.
power chords are good to show beginers. bar chords too.
you can spend alot of time just showing her new chords and playing peices of songs and stuff.
a beginner probably isn't going to be to thrilled about a bunch of exersizes. and i would suggest not even trying to introduce theory. it wont make sense to her yet. try not to turn guitar playing into work for her yet or she may lose interest.
after you spend time on open chords, power chords, and bar chords, show her some stuff with single notes in it. like Pink Floyd's "Wish You Were Here".
make your way to the major scale.
now you can start explaining a
little theory.
the musical alphabet for starters.
the notes in a C Major scale.
why C E G are the notes in a C major chord.
why C Eb G are the notes in a C minor chord.
keep it as simple as possible, and explain everything using the key of C first, because of the no sharps or flats thing.
now for some pentatonic action.
you can play her some blues chord progressions while she plays around with the pentatonic scale.
then show her the bluesy chord progression your playing... the 12 bar blues. show her some turn arounds she can use when playing it.
you can take pretty much any blues song on a cd and play it, and improv with over it with the pentatonic scale.
you can show her the blues scale as well.
minor scale. show her how it relates to the major scale (really, relate every new thing you teach her back to the major scale). play around with that etc etc.
you should be showing her proper technique all along the way. pay attention to what shes doing with her hands.
after she has a handle on picking all downstrokes, show her alternate picking (keeping things simple, of course, no paul gilbert YET!

).
pull offs. hammer ons. natural harmonics. artificial harmonics. etc.
give her something new when you think she's ready for it, and don't overload her with to much stuff at one time.