Hi
First of all , you must download datasheets of the components .
then read them carefully , specially application notes .
if some datasheets don't have application note , you must download some .
then choose the most important part of the board
and with the help of beep sound of a multimeter find connections
along side that open a schematic document in protel etc .
I advise you not to use a paper , do everything in schematic
one by one complete your schematic and don't matter
that the lines(tracks in schematic) are untidy , freely make lines (tracks)
at last you will make them tidy
then check everything and complete your schematic
finally ,
scan all layers (high quality)
use photoshop or illustrator (Ai) (illustrator is better than photoshop)
all coppers must be black and non copper parts must be white
so holes and via's must be white
use bmp2pcb software to make a pcb from your bitmap files(black and white file)
do the same thing for all layers , you could rub the top layer and
remove it to reach the next layer
at last place the componets from your schematic and find possible errors
NOW YOU HAVE DONE EVERYTHING
Have Fun