I just got my 12 string from musicians friend, and Ill be damned if i can't figure out how to tune the thing. Can somebody help me?
Don't Let me down!
I believe its tuned the exact same way as a guitar. 12th and 11th string Low E 10th and 9th string A and so on
I think EADG have all the octave strings tuned up an octave and the others have the paired strings tuned the same. Not absolutely sure
Taken from the Tuning Thread...

12 String tuning:
SilentDeftones answer:
Okay, you have 6 strings tuned normally, EADGBe. When you get a pack of strings for a 12-string guitar, you should have a set of normal strings and a set of thinner strings.

You have:
e - normal high E string
e - unison (same) to other high E
B - normal B string
B - unison to other B string
G - normal G string
G - one octave higher than other G string
D - normal D string
D - one octave higher than the other D string
A - normal A string
A - one octave higher than the other A string
E - normal low E string
E - one octave higher than the other low E string

The ones that are higher should have more tension.

Logz Answer
Im not sure how to tune a 12 string, but from what SD wrote ill give it a go...

Im assuming you know how to tune to standard, so im skipping that part. If you dont, check the very top of this thread.

This is hard to explain!
Look at this tab:

[font="courier new"]

1 2 3 4 5 6 7 8 9 10 11

This is how you should use this diagram to tune....

at the bottom of the diagram theres numbers 1 - 11. Start from 1 and work to 11.
But tune in this order: 2 - 4 - 6 - 8 - 10 - 1 - 3 - 5 - 7 - 9 - 11

the first set of number ( 2 4 6 8 10 ) is tuning the normal strings to standard tuning. the numbers after, are tuning the extra set.

You should know how to tune to standard, so ill skip that part, as for the second set of numbers ( 1 3 5 7 9 11 ), retune the bottom number to match the top number.

If you've got any other tuning questions: https://www.ultimate-guitar.com/forum/showthread.php?t=356567
Lets start by numbering the strings of a normal guitar.

1 - E4
2 - B3
3 - G3
4 - D3
5 - A2
6 - E2

On a 12-string, each of these strings is accompanied by a second one that may be thinner or exactly the same as a regular guitar string. We'll call these 1a, 2a, 3a, 4a, 5a, and 6a.

1 - E4
1a - E4
2 - B3
2a - B3
3 - G3
3a - G4 (an octave -- 12th fret -- above the 3rd string)
4 - D3
4a - D4 (an octave -- 12th fret -- above the 4th string)
5 - A2
5a - A3 (an octave -- 12th fret -- above the 5th string)
6 - E2
6a - E3 (an octave -- 12th fret -- above the sixth string.

Alternatively, you can tune all of the strings a tone down and place a capo on the second fret; this is done to relive the extreme neck tension and prolong the guitar's life.