When I'm transposing stuff... I gotta do this...I write this across the top of the page I working on...
abcdefgabcdefgabcdefgabcdefg...
That way I can count up or down as I need to... So from G to say C is up 3... then just move the chord names up 3 on my homemade chart...
Now I understand there are people out there who can do this kind of stuff in their heads, or can look at those squiggles on a piece of "sheet music" (?huh?) and can tell the key, the chords and even the melody...
To them I send the 2 finger slaute!! LOL! Lucky bastards
;-)