1/2 yard of cotton broadcloth
10 - 15 yards of lace or ribbon
1/8 yard fusible interfacing (optional)
1 yard stick
pencil or material marker
hook and eyes
needles
thread
 

Take your neck measurement . Make a band at the desired width (I prefer 1.5 inches) and length of neck.  Use what ever method is easiest. The simplest way it to cut a rectangle that is length + 1 inch and width + 1 inch. Iron interfacing on one half of length. Sew fabric into a tube. Iron, close and top stitch  Use the same technique to make cuffs except make the cuffs twice the width of the ruff. (When making neck ruffs that will be worn under a doublet or partlet use the cuff technique

First, determine the number and spacing of pleats. I have found that lace and other thinner materials look best with pleats every centimeter. Thicker fabric such as ribbon look best every half inch.

Mark the pleats on one side all along the length of the band. Turn the band 180 degrees to work on the parallel side.

THIS IS IMPORTANT

Place the first mark 1/2 of the pleat distance from the end of the band. (i.e. 1/2 inch = 1/4 inch) Then continue the marks along the length of the band. 

The end result is the marks will be offset from each other. An imaginary line connecting the marks back and forth between the two side would look a zigzag.

When marking the cuffs or a band that will be worn under a doublet or partlet first draw a line parallel to the length of the band at the desired width of the ruff. I usually make my width more narrow then the neck ruff. (example 1.5 inch neck width would have 1 inch cuff width)

(NOTE) When making a neck ruff using the cuff technique do not make the ruff part too wide because it must set on top of a collar.
 

There are different ways to attach the ends. I first tried ties but they kept getting tangled in my hair. I settled on hook and eyes. On neck bands I place a set on on the upper and lower part, on cuffs I place an additional set in the middle (see cuff figure in Step 2)