This is the common and halakhically precise type of tying: 

The bundle contains sixteen tzitzit strands (four long ones and twelve short ones.)  Separate these into four groups each containing three short strings and one long one.  The long strand is called the Shamash and is used for the windings.

Take one group of 4 (3 short and 1 long) and hold the ends together evenly.  Push them through the hole in one corner of the tallit.  You can use a tweezers or crochet hook to pull through if the hole is very small.  Pull the 4 strings all the way through and even with the other three short strings.  The Shamash will be longer than the others.   With four strands in one hand and the other four in the other hand, make a double knot approx. 1” from the edge of the material.

 In order to fulfill the mitzvah of tzitzit, it is customary for you to say l’shem mitzvat tzitzit, “for the sake of performing the mitzvah of tzitzit,” each time you tie a knot.

Make a simple slip knot in the four strings without the Shamash.

Next, pull the Shamash to one side and, holding the seven shorter strings in one hand, wind the Shamash around in a spiral seven turns.  It doesn’t matter if you wind to the left or right, but count the wraps very carefully.  Make sure that the wraps start and end on the same side.

Now separate the strings into two groups of four and tie another double knot.

Again, take the Shamash to one side and wrap 8 times followed by a double knot.  Continue wrapping and tying in the same order seen in the illustration to the left ending with a final double knot.

Be sure to carefully check the number of wraps before each pair of knots.  Repeat for the remaining three corners.

A Sephardic tying adds another dimension to the pattern.  Each time the Shamash is brought around, take it under the previous wind before winding it further.  This will produce a curving ridge around the tzitzit. This should be practiced before trying it on the tallit. 

** If you are left-handed, substitute the word "right" for left.

When all four corners are completed, you may gather them together and trim if they are too long.