@ScottishMouse A quick answer, based on a combination on self-reflection and writing eBay listings over the years - don't daydream! Or rather, if we do, which I certainly do, try and catch the fantasy of what I'm imaging my life will be when I wear x or y garment, and then be sure to subtract that from the actual purchasing decision :)
I used to write a great eBay blurb, but realised buyers were getting seduced by the pretty words, not reading the factual details properly, then finding fault/leaving negative feedback/finding ways to inveigle a refund etc. Now I'm strictly matter of fact information - fewer, slower, probably lower value sales (no auctions for the same reason), but fewer hassles too.
Try and restore humdrum reality. How does it look from all angles, lights, with different outfits? How does it fit as I move in it? Do the measurements correlate with similar items that fit well? What are the care instructions? Do I need it, when am I going to wear it, and so on? I never manage to keep everything in sight, but it's easier, for me, when I'm not subconsciously dressing an alter ego adventuring through a parallel life to mine :D
Don't know if that helps at all!