Most people overvalue used wares. List them at 50-percent of today's average new price, plus 10-percent for negotiating wiggle room.
Many sellers omit vital ad info. Look up the manufacturer's specs and list them, including wheel offset, bolt pattern etc. Research and list other cars they'll fit. if any. It will cut down on the morons asking if they'll fit an Escalade. Include at least a half-dozen good clear photos taken with a real camera - not a cellphone. If you have a photo of your car with them on it, include it. Get a $5 Canadian Tire depth gauge and include the tread depth. If a wheel has curb rash, say so.
Don't agree to a lower price over the phone or by e-mail. Suggest the person look at them first. Less chance of getting double-whammied on the price.
Advertise early. Be patient. October is the month for selling used winter tires. If the ad doesn't work after 10-days, reword and re-post.