I went down two sizes from my "true" size. According to my measurements I should be in a size Medium but I made this one Extra Small.
I cropped 3" from the length of the body. The pattern doesn't have a shorten/lengthen line but it is a squared off shape so I simply removed 3 inches from the bottom of the front and back pattern pieces. Don't forget to move the notches at the bottom front if you decide to do this too!
I made the sleeve 3" long using the boxy sleeve pattern. I measured 3" from the top of the sleeve at the weird pointy bit and drew a perpendicular line across the sleeve pattern 3" down to leave me with a short sleeve.
I also went a little crazy with the buttons just because I like the look of a bigger button on pretty much everything.