Here's a quick look at a basic pull-on pant with a 1.5" elastic for the waist. While this pattern appears to be a simple construct, it's far from it. This pattern is the outcome of about 4 slopers and countless hours in drafting time. The perfect fit is not elusive, it's just a lot of patience. In the end, it's worth every last second. Once it's done you are on your way to never having to buy an ill fitting RTW pair of pants again.
Here's an overlay so you can really look closely at the difference between the Pant Front and the Pant Back:
Pic 1 Shows the Front and Back Matching at the side. The orange wedge depicts how much higher the Back is than the Front. Pay particular attention to the calf area. You want to keep the side seam straight down the side of your leg. In order for that to occur with my pattern, I needed extra room for the Back piece in the calf area. Look at the crotch point. See how much I need in the back than the front in order to get that placement perfectly located to fit me. Also note that the Front piece from the waist to the high hip area is larger so the seam in that area rolls toward the back just slightly.
Now take a look at Pic 2. Back and Front are aligned at the center points. See how the crotch point of the Front is higher than the Back. The standard is about .5 inches, but for me it's just under.
This sloper is now the basis for every pant I make in the future. Ease is taken out for stretch pants and ease is added for woven pants.
Here's the final Pant:
