Put it on craigslist, make a burner email for the car, advertise it at 800-1k higher. You'll almost always end up coming down off the price unless you are holding something people are truly beating your doors down to get from you. Start higher and come down. Wait a week or so, drop it 250.
Clean the ever loving shit out of it. Inside, outside. Dump a can of seafoam in the gas tank when it gets down about 1/2 or lower. Run that out and refill it.
Be prepared to negotiate some if there are major leaks, transmission shudders, shit brakes, bald tires etc. that's why you start high. Don't negotiate on stuff that is wear and tear. It's a used car, it's gonna have a few blemishes.
With things being the way they are, expect to wait a few weeks before you sell it. I've sold all my old cars on Craigslist, never taken longer than a couple weeks. Advertise on other things too. OfferUp etc.
Go to Wallyworld and get a for sale sign to stick in window when it's parked. They're like 2 dollars and don't have an expiration date. Put down a layer of masking tape over the signs information area, write on those and rip em off when you're done. Take that bitch back to Wallyworld and get your two dollars back. Fuck Walmart.