As promised, a tutorial on converting a normal/straight sleeve into a puff sleeve.

GCSE Art rears its ugly head

If you prefer to add fullness at the cuff, you only have to do the same thing, but upside down. Logic, eh? A puff with gathers at the cuff could be elasticated or have a lovely ribbon tie affair to create the gathers, if your sleeve design is cuffless.

On my wanderings around the internet, I found this really helpful and clear post on adapting sleeve patterns for other styles from ikatbag.