Draw a simple waistline shape
Sketch the hip area below the waist
Add two long leg shapes extending downward
Separate the legs with an inner seam line
Shape the crotch area with a small curve
Define the outer leg contours
Add knee positions if needed
Narrow or widen the lower legs depending on the style
Draw the cuffs or hems at the bottom
Add pockets, belt loops, and fly details
Refine the outline and erase guide lines
Add folds and wrinkles around the waist, knees, and ankles