1) Form a loop about 10 inches
from the line end, and grip it tightly between finger
and thumb.
2) Whilst continuing to hold the
loop, take the line end and wrap it once around both your
thumb and the loop, wrapping away from you. This wrap
is what will eventually form the loop.
3) Make a second wrap in front
of the first wrap, but this time around the loop only.
Hold it under your thumb.
4) Slip the first wrap off your
thumb and pull it through the open loop of line. Draw
the knot tight closing the original loop. Trim the tag
end and you're done.