What L's costume lacks in detail, it makes up for in his character. Worn jeans and white long sleeve T-shirt is all you need, plus a proper wig found online. I wore the wig as is, then styled it more like in the anime series later. I practiced slouching like L, his finger biting gestures and the way he talks. It was a lot of fun to be L. I cosplayed him from 2008 to 2009.