I would start by knocking up a nice web page for it, with lots of photos
Not just a lot of photos but also some honest info about the planes equipment (mode-S, ELT?), maybe a W&B schedule, some highlights from the maintenance/damage history, information regarding lifed items, some links to reviews and so forth. Anything a potential buyer would be interested in.
A lot of planes on e.g. planecheck.com only have three pictures and an asking price.