I've sold a fair number of items on ebay, never any real issues but a few tips.
I only use Buy it Now and start with a highish price. If you get watchers you can always send an offer or if needs be drop the price latter.
Only deal with people via ebay. I have listed items for £2-3K and had a string of messages about buying for a relative, going to vist them overseas etc. They all end eventually with Western Union, just don't. You can also so look at feedback if they only created the account today, avoid, if it's an old account that has been dormant for a while, avoid (it's been hijacked). I've only had these issues on big ticket items and they are easy to spot.
Good photos and lots of them are worth the effort, if it has a serial number I like to include it in images so there is no question if someone wants to return something.
If people say "what's your best price?" I tend to ask them why they feel the asking price is unreasonable, sometimes I'll move on price especially if they have bought from me before.
Be professional. I am a private seller but some people think I am a business because I behave in a business like way. I reply to questions swiftly, I offer a 14 day return on goods over £100 (i think that is fair if someone is spending that kind of money and I have confidence I have been honest about the listing). I have comprehensive descriptions and clear indicators of any issues, none of this "sold as seen", "unable to test" BS
I leave positive feedback for buyer when I send the goods out. I feel all one can ask of a buyer is to place an order and pay proptly, I thinks it's a bit shady to withhold feedback in case they want to send it back or whatever. DO your job and you will get good feedback and no issues. Behave like a shady character with weasel words, withheld feedback, no returns etc and you will reap what you sow.