This is pattern drafting at it's basic!
This is a very simple pattern which would be classed as a T-shape, there is no shaping in the waist or the shoulder. Once finished you can add design lines and choose how to cut it up for your finished garment.
It's an ideal pattern for a peasants shirt or an outer smock starter.
You'll need the following measurements:
Neck
Chest
Shoulder length
Arm length
Depth of armscye (how deep you'd like your armhole to be)
Cuff measurement
Finished length
N.B: If you've not followed pattern drafting instructions before they're very simple. The points are given on the diagram e.g. 1, 2, 3, 4 etc. And the instructions are given as 1-2 = 1/5 of neck. So you need to find the points 1 and 2 on the diagram, copy thosepoints on your pattern with the distance of 1/5 of the neck measurement. Make sure you check the direction of the points, up, down, left and right (also known as across). And square up or down to draw a line from the point you are on straight up or down.

(The diagram is not to scale)
Drafting directions:
Mark point 1 and square across and down.
1-2 = 1/5 of neck measurement minus 2mm
1-3 = 1/5 of the neck measurement
1-4 = down 2cm
Draw in the neck curves
4-5 = armscye depth (measure down the depth of the armhole) and square across
3-6 = shoulder length plus 1cm (6 marks the shoulder point)
6-7 = arm or sleeve length (add 1.5cm for outerwear)
7-8 = 1/2 of cuff measurement
5-9 = 1/4 of the chest measurement plus 1/4 of the total ease required (e.g. outerwear may be 30cm ease, so add 7.5cm to your chest measurement)
4-10 = finished length of garment, square across
9-11 = square down from 9 to touch line from 10
Join the dots as indicated on the diagram to create the pattern.
N.B: The front and back of the pattern are drawn at the same time, the neck line for the back is 3-4 and for the front it's 2-3. Trace off the front and back pattern pieces for use.
In it's simplest form the pattern can be use as it is without any style adjustments. If you join the back and front pattern pieces together at the shoulder, you can use this to cut your shirt as an all in one pattern (remember to cut the fabric on the fold to create the left and right sides of the shirt equally). Just add seam allowances and you're ready to go.
Style lines
Now that your basic shape is finished you can add your style lines You can create sleeves rather than having an all in one, add a yoke and curves in areas if you like, the pattern can become very versatile.

(Image is not to scale)
Once you've decided on your finished design you can cut up the pieces. Remember to add the seam allowances!