In most categories preparing an item helps. In this one it is usually the expensive mistake.
Refinishing or polishing
The surface an object has acquired over its life is a large part of what it is worth, and removing it cannot be undone. Clean lightly, say what you did, and stop.
Not showing the back or the underside
Repairs, replaced parts, marks and old labels are all there. A listing of the front has described the furniture a buyer can already see.
Not using the trade's words
Original, repaired, restored, married. Good restoration is designed to be invisible, which is exactly why it has to be written down. The four words.
Guessing a date confidently
"I believe early twentieth century but I cannot confirm it" sells better than a date that unravels in the chat.
Deciding delivery after the sale
Heavy, fragile and awkward is where delivery goes wrong. Decide courier, your own delivery, or collection before the show — collection is agreed before bidding. How pickup works.
Posting glass in a frame
Broken glass does not just break; it damages what it was protecting.
Not measuring
Scale in a photograph is unreliable, and buyers discover it after delivery.
The one that costs most
Undeclared restoration. It is the claim that, once found, makes a buyer re-read every other sentence you wrote.
Questions people ask
Should I repair a wobbly chair first?
Describe it instead, and say whether it is usable now.
Is woodworm a deal-breaker?
Disclose it and say whether it is old and inactive.
Does a valuation set my price?
No. An insurance valuation answers a different question. What an antique is worth.
More: selling antiques, packing them.