Clean it completely and stage it. Then take a couple of dozen pics of Everything from every angle. Then detail its history with everything you know or can remember about it.
We listed on CL with 24 pics and everything I knew about it. Sold it to first responder the next day and had a disappointed #2 responder who badly wanted to buy it. I had priced it as a good/fair deal for both parties.
When I posted to CL, I emailed everyone I knew locally and told them what my bottom $ was and that they or anyone they knew could have it for that by asking. I always add about 10% to asking price because its seems that some folks get all pissy if you wont bargain with them. I then immediately tell normal people how I am pricing and my bottom $ when they ask.