My only two cosplays:
The Medicine Seller from Mononoke/Ayakashi - the eye markings are a bit wrong, but if I remember correctly my friend did that without a reference image. I also learned how difficult it was to walk in geta that day.
This was at Aberystwyth Anime Society's cosplay social in 2010, though I also wore it to a Halloween fancy dress competition the same week.
And
Shidou Maria from Maria+Holic, which was at Telford Expo in 2011. Walking around all day without my signature otaku glasses and backpack was probably the hardest part, aside from that it was great fun.
I'd do more, but I lack the creativity/patience to actually come up with a good costume on my own. These were largely a collaborative effort with a friend at university.