How to Tie Scarves
The best video I've seen is this youtube video from Wendy's Lookbook.
Illustrated instructions are at Texeresilk Ultimate Scarf Tying Guide. Click on any of the illustrations to get the step-by-step instructions.
Boa
Wrap scarf in a loop around your neck, take excess and keep wrapping it around the loop. Tuck the ends into the loop. You can make a bigger loop for a lower drape on the Boa.
European Loop
Fold the scarf in half forming a loop on one side. Slip both ends through the loop. You can also Fold the scarf in half, forming a loop and hold the loop in one hand and both ends in the other. Twist the scarf so that the part the goes around your neck is compacted. Then put it around your neck and slip the ends through the loop.
European Loop with a Twisted End
Fold the scarf in half forming a loop on one side. Insert one end through the loop. Twist the looped end and slip the second end through the new loop. One advantage of this tying method is that the loop is very stable and you can wear it on your shoulder, too.
Ascot 3 ways
Drape the scarf over your shoulders then bring one end up over the other in a simple tie. Position the tie so that one end completely covers the other.
Braid
Fold the scarf in half forming a large loop. Hold the loop end in one hand and twist until the scarf is compacted. Slip BOTH ends of the scarf through the loop. Twist the loop and pull both ends through the loop again. You can do two or more repeats of this step to form a braid. You can also wear the braid to the side ( see below).
Infinity
Tie two scarf corners together in a small knot. Twist the scarf once, then slip the knotted end over your neck. Hide the knotted end in the folds of the scarf around back. You can also spread the scarf out and wear it wide (see below).
Vest Tie
Fold the scarf in half so that the end are together. Take two ends of a large scarf (you need 72" or longer) and make the first half of a simple knot. Pinch a little bit of fabric from the edge at the middle of the back. Lay the MIDDLE of the back over the tie and complete the knot. Now you have the middle of the back and both ends tied together. This forms two armholes. If you wear the armholes up high, you get a vest. You can also wear the armholes low and wear it like a shrug or shawl.
Simple Drapes
Tie a knot off to one side or in the middle. Or put one end through a bra strap to hold it and drape the rest of the scarf over that shoulder.