Bryan G- Hey dude, how do you choose the right Cardigan Size especially if you would want to wear it over a long sleeve shirt without wanting to look fat?
Terence Sambo- Most brands like to make their Cardigans in medium or large widths to accomodate more people since majority of the customers are slightly bulky. If the width is always a concern for you i suggest you go to the stores directly and try them on or have a tailor take a few inches off the sides, as long as its your Size it would still look good.
The Cardigan featured is by Farhi & retails @ Asos.