This is the common and halakhically precise type of tying: 

The bundle contains 16 tzitzit strands (4 long ones and 12 short ones.)  Separate these into 4 groups each containing 3 short strings and 1 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 them up with the other three short strings.  The Shamash will be longer than the others.  Hold the four short strands (without the Shamash) in your left hand and the other four (including the Shamash) in your right hand and 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.

Now, pull the four strings (without the Shamash) to the left ** and make a simple slipknot at the bottom so they remain together until the tying process is finished.  It will be removed at the end.

Now pull the Shamash to the right and while holding the other seven shorter strings in your left 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 the two groups of four and tie another double knot.

Again, take the Shamash to the right side and wrap 8 times followed by a double knot.

Continue wrapping and tying in the same order seen in the drawing and ending with a final double knot.

Remove the slipknot holding the four strands together.

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, you can substitute the word "right" for left!

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

You can also click here to watch a video on tying tzitzit.