basicly with a great deal of effort
split ur model in half and UV in low poly at first
then wen ur done line up the UV's so that the go down the centre line of the UVT editor
miroor combine and merge ur model
the UVs shold now be mapped

now the knitty gritty

u want to break ur model up into setions ie. arms,toes body ect
but wen u first map i start with parts of each and sew them up
this is where the checkered texture becomes ur friend so u can see where it is stretching or squashing
int eh UVT editor fill up as much space as u can to optimise painting size and 'white space'

this will take ages an theres no real short cut unless u try peltmapping

utilise the otion like planar,automatic spherical ect
as these can do some of the work leaving u to tweak them

final tip save in increments so u can go back to a part u know is good incase u mess a bit up