Determine the position you want the waistline of your pants to rest when worn and measure around this portion of your body. The measuring tape should be straight and flat against the body, yet comfortably loose.
Hips
Stand with your heels together and measure around the fullest part of your hips; the measuring tape should be straight and flat against the body, yet comfortably loose.
Inseam
Remove your shoes and stand up straight. Start the tape measure high in the crotch. Keep the tape straight, and measure down along the inside of your leg to where you want the pant to end.