The following is brought to you by the power of ASCII Art! It is a representation of how to tie a Windsor Knot, and is based on what it would look like when observing a right-handed person tying one.

1. Pass the wide end of the tie over the narrow end.

      \ \ | |
       \ \| |
        \ \ |
         \ \|
          \  \
          |\   \
          | \   \
          | |\    \
          \ / \     \
           V   \      \
                \      \
                 \       \
                  \      /
                   \____/
2. Loop the wide end around behind the narrow end.
         _| |__
     \ \/ | |  \
      \ \ | |_  \
      /\ \| | \  |
    /   \ \_|_/ /
  /    / \_____/
/     /   | |
     /    | |
    /     | |
   /      | |
  /       \ /
 /         V
/
3. Loop the wide end down through the "V" made by the tie under your neck from the front, forming a reverse-tie.
     \  \ | |
      \__\|_|___
       |       |
        \     /
        |\___/|
       |  | |  |
       |  | |  |
      |   | |   |
      |   | |   |
      |   | |   |
     |    | |    |
     |    \ /    |
           V
4. Now, pass the wide end back over the nice triangle knot again.
                    \  \ | |
  ___________________\__\|_|___
 /                            |
/                            /
\                      _____/
 \             ____----  | |
  \______------          | |
                         | |
                         | |
                         | |
                         | |
                         \ /
                          V
5. Then back up through the "V", this time from the back of the knot.
  
    /         
   /  \ | |  
  /   _\|_|___ 
 /   /        |
|   /        /
\_/_________/
        | |
        | |
        | |
        | |
        | |
        | |
        \ /
         V 
6. Now finally, thread the wide end down through the loop formed by the triangle from the first knot in Step 2.
        \ |  |
        _\|_ |__
       |        |
        \      /
         \____/
         /    \
        /      \
        |      |
        |      |
       |        |
       |        |
       \        /
        \      /
         \    /
          \  /
           \/
Pull down on the wide end of the tie to adjust the width and tightness of the knot, and then pull down on the narrow end of the tie (pushing up on the knot) to place the knot over your top button.