(i dont really know how to tie a tie so just sharing what i've learnt so far.. )

To tie the Half Windsor Knot, select a necktie of your choice and stand in front of a mirror. Then simply follow the steps below:


1) Start with the wide end ("W") of your necktie on the right, extending about 12 inches below the narrow end ("N") on the left.


2) Then cross the wide end over the narrow end.


3) Bring the wide end around and behind the narrow end.


4) Then bring the wide end up.


5) Pull the wide end through the loop and to the right.


6) Bring the wide end around front, over the narrow end from right to left.


7) Again, bring the wide end up and through the loop.


8) Then, bring the wide end down through the knot in front.


9) And -- using both hands -- tighten the knot carefully and draw it up to the collar.

from http://www.tie-a-tie.net/halfwindsor.html