In regards to drafting, there are a number of considerations to make before starting. These are some of mine.
Measurements and photos.
Take good measurements. Have the person being measured wear a snug fitting tshirt.
Pin twill tape or an elastic at the waist when measuring. Take balance measurements of your choice.
Take photos, with the waist tape in place. Take front, profile and side photos in good light.
Look at the numbers. I usually make a chart. Height divided into 1/2, 1/4, 1/8,
Chest, waist and hip divided the same. Calculate working scale 1/3 of chest plus 6 inches or 15.2cm.
Compare the measures against standard proportions.
For instance, back length is usually 1/4 of height. Is the measurment you have longer or shorter?
Was the waist tape in the correct position? (Hint, elbows are usually at the same level as the natural waist).
Be familiar with the draft you are using. Try the draft a couple of times uing the sample measures, make sure you understand it before embarking. I actually have my own draft that I have developed over many years, but I often look at other sources for inspiration and refinement.
Analyse the figure.
The profile photo is usually very helpful here. Is the figure old or youthful, slim, average or bulked up with exercise, bony and angular, thick, soft, portly, stout or corpulent? With figures who carry excess weight, I think about their frame and what size they would be without the excess weight.
Start with the neck. Is the measured neck small or large in comparison to the chest size?
For instance, I have three gentlemen who measure 38" chest. One has a 16 1/2" neck(larger than proportionate) one a 15" neck (proportionate)and the other a 13 1/2" neck (smaller than proportional)
Look at the profile of the back. Is the upper back built up, or average, is the head forward?
Look at the stance, posture. Hip forward? Straight and balanced, stooped or erect?
Look at the seat. Prominent, averge or flat?
At the front of the body look at the position and shape of the chest. Is it prominent, or average?
Look at the front position of the waist. Is it in the same plane of the chest, or does the waist protrude beyond the chest plane?
Shoulders. Look at whether they are average, sloping or square. Is one side lower than the other?
If one side is dropped look at the hips too. Often one hip is higher than the other.
Legs. Straight, bowed or knock kneed?
all of these things need to be taken into consideration before drafting for the individual figure and help in the fitting process as well.