In addition to the advice above, I like to make sure that my auctions end on a Sunday afternoon when everyone is looking at ebay. I've got some saws for a steal when they ended at like 10:00 AM on a Tuesday. (I work at night.) Alot of guys use sniping services, but many don't and items will go higher when sold on the weekends.
Don't BS the buyers. Some guys will bite, but they're morons who don't know any better. Yeah, you can sell an 029 for $500, but most of the time it'll go fair market or less if you BS. Explain as much as you can about it. Make it clear the saw has been made ready to sell, unless it's being sold as a parts saw. Put in new filters, carb kit if it needs it, tune it and tell them every little thing you've done to it. I've only sold saws I've rebuilt, so I mentioned how I honed the cylinder, rebuilt and adjusted the carb, cleaned the spark arrestor, blah, blah, blah. It's not BSing, but it lets the casual and serious buyer that you've taken care of it, and they're not going to have to put $70 in kits and filters as soon as they buy it.
And if it's on old metal saw, paint it. I've made so much extra money on good saws just because they were painted and looked good. People go ape over a good looking saw.
And kill them with honesty. If they know the biggest problem the saw has is the small crack on the rewind, that makes the saw more attractive.
Jeff