Start with Accurate Measurements:  If it has been a while since you have measured yourself (or whomever you are sewing for) do it again before you start a new garment.  Make sure to use your larger thigh measurement for pattern drafting.  After you have drafted your pattern, check the measurements of your drafted pattern at crucial points before adding seam allowances to determine if the pattern will fit your body. Check your upper thigh area on the pattern to make sure there is enough room to fit your thigh. Make any adjustments at this time.

Check Your Grainlines:  Grainlines play a crucial role in the stability and fit of your garment. Always draw your grainlines first and make sure they are parallel to the center front/back and perpendicular to the floor. This will help maintain the integrity of the fabric and prevent twisting. I know this is obvious to most of us, but I have had to check myself when I am sliding the pattern that I am drafting up and down over the master pattern to draw the full length of the pants. After sliding your draft, make sure you are back on grain and extend your grainline. Another time to become off grain is when shortening a pattern. Always draw an extended grainline when folding up a pattern piece for shortening, make sure the grainline is overlapping over itself, and make sure your fold is parallel with the hem and any other horizontal drafting lines.

Check the Fit: When trying on your muslin mock-up, pay special attention to how the garment fits around your legs. Look for any signs of twisting or pulling. If you notice any issues, such as twisting or tightness, I'll teach you how to address those issues next.

Consider the Fabric: The type of fabric you choose can also affect how your garment drapes and fits. Certain fabrics have more stretch or drape than others, which can impact the overall fit and stability. Be mindful of the fabric's characterizes and how they may influence the result. Occasionally, the fabric itself is off grain. There are ways to stretch it back to being on grain, but you might ask yourself if that fabric is reliable and worth the effort.

And finally...One of the major causes of the twisted leg is an insidious issue that can be incredibly challenging to find and address. I have created a half scale drawing of the Pants Back Master Pattern to help demonstrate one of the causes and a few corrections of the twisted leg. The problem can occur when we are trying to fit our bodies into traditional pattern drafting curves or styles that don't match the shape of our bodies. The insidious culprit here is the inward curve after the crotch point on the pants back of some commercial pants patterns, or how we have drafted them. This inward curve can either create by itself a pulling/twisting relationship between the inseam and the outer seam of a pair of pants. Another problem could be that this inward curve is not leaving enough room to fit the inner thigh.