I took a collared shirt and just removed the collar and recoloured the buttons black. I had originally planned on making his suspenders, but ran out of time and ended up settling on a pair I already had.
His scarf is made from two yards of yellow cotton, with a seam about 2/3's of the way down (sadly), and then used double fold 1" black bias tape for the trim.
For the wig, I used a normal black wig, and then pulled a thin layer of my own hair out and styled it over it, to have his widows peak. Cosplaying him again, when my hair wasn't black, I used a black aquapaint to recolour my hairline and other visible parts of my hair.