Shoulder:

You have to measure from the direction of one shoulder, across your back to the tip of your other shoulder.

Chest:

You have to measure the girth around the entire area of the chest.

Natural Waist: 

You have to measure the girth approximately the thinnest area of the waist.

Lower waist:

You have to measure the girth around the entire area of the waist.

Hips:

You have to measure around the entire part of your body, above the top of your legs.

Sleeves outseam:

You have to calculate from your shoulder seam, with your arm barely bent, to the tip of your wrist.

Pants inseam:

You have to calculate from your crotch point to your ankle bone.