I was a top rated seller with 100% feedback on Ebay for many years with an Ebay store and what not. Their fees kept going up while they were also double dipping with paypal fees to the point where it wasn't worth it for most items and I closed down my Ebay store and stopped selling frequently. Now I only use it occasionally. They decided several years ago that it was easier to make money with less headaches by catering to businesses selling rather than individuals like when they started.
Take nice clear pics inside, outside, front, back , boxes, part # labels etc.
For an Item like a NOS scoop Ebay is THE to sell and I found the best way was to start the auction at the lowest amount I would be willing to take for the item (remembering to add 15-20% for fees). Schedule a 7 day auction to start on Sunday night (most people are home to bid) at 8 PM Pacific time (Ebay's on Pacific time) so that it would end at 11 on the East coast. Folks in the East will stay up to 11 to bid at the end and folks out West are usually home from activities to bid by 8.
If you have more than one related item like a shaker scoop, shaker base, and shaker gasket then list them separately. Make a note in the description of each item indicating that buyers should look at your other auctions to see the related items. You'll get more total $ from the sales than if you list a shaker, base, and gasket package. Also mention in each auction that you are willing to combine shipping on the items if they win more than one of the auctions.
For an item like the shaker. Box it up and check for the shipping cost to the farthest place in the 48 states. List that price in the auction stating "shipping in the 48 states only" and don't get involved in any sales out of the country. I did a lot of sales all around the world and the small margin the winning bid is over a 48 states bidder isn't worth the hassles for an occasional seller.
Some forums have an Ebay listings discussion section. If you're not a forum member get someone who is to post about the auction. Example: transamcountry.com has an Ebay discussion section and I'd be happy to post there mentioning your NOS scoop. The more eyes that see the listing the higher your sale price will be.
I could sit here and think of tips all night but need to go sleep.