Align the outer and inner
seams of one leg of the slacks
Fit the outer and inner seams of the leg together, from bottom edge to crotch, hold so it does not move, and iron the edge with pressure.
Move the iron in a zigzag motion, mainly along the seam, position the crease line, then iron the crease with pressure.
Use the rounded end of the ironing table when ironing the hip and waist areas of slacks.