Here are a few tips on pleating!
The first step whenever pleating is MAAATH! The point of pleating is to fold excess fullness to the waist measurement in an organized manner. Unlike gathering, pleating takes a lot more attention and preperation, but the result is a noticeably detail.
To begin, determine A) the total amount of fullness; B) the waist measurement; C) the difference between the two. i.e.:
Waist=26.5; Fullness=45; Excess=18.5
From this, you can determine how many pleats you want and how much fullness will go into each pleat. It is simplest to have all the pleats be relatively the same, but you can of course be adventurous and have you pleats increase in size as they go around the body to push more of the fullness to the back. It is always helpful to draw pictures:
Here you can see that I will have five 1.5″ pleats and one 1.75″ pleat, with 3″ at the Center Front (CF) and 2″ in between all the following pleats. I noted which measurements were pleats with a ^ symbol.
Now you can beginning marking your pleats on your fabric. I use light pencil marks and notations on the inside. ALWAYS mark your CF first and move out from there. I mark my pleats with little vertical lines ( | ). If they go up into the seam allowances, they mark the beginning and end of pleats. The lines that go down away from the seam allowance note which spaces that ARE pleats.
Then, I pin all of my UP lines with DOWN lines between them together. This not only makes it easier to form the pleats, but always gives you a chance to MEASURE the waist to make sure it is the right size and make adjustments before pleating everything completely.
There several kinds of pleats you can do from the point we are at now, but the most common are Box/Inverted Box pleats and Knife pleats.
A box pleat are two pleats that face away from each other, and an inverted box pleat are two pleats that face toward each other. A knife pleat are single pleats that lay in one directed, usually aerodynamically around the front of the body towards the back.
Stitch your pleats in place above the stitch line with a stay stitch (around a size 4) to hold in place for when you the skirt to a bodice or waistband.