I sell fashion items, and I personally prefer the 'just the facts, ma'am' approach when it comes to descriptions.
I know elaborate descriptions work for some when it comes to fashion items, but one of my pet dislikes is ones that tell people how they will look and/or feel when wearing something (I mean stuff like - you'll look absolutely ravishing and feel like a princess with this thing on... kind of stuff). If I think something is pretty, then I'll say so. If it's a handmade item and inspired by something well known, I may mention that too, but otherwise it's strictly item specifics.
Fast postage can definitely be a selling point, there are items out there that are more time-sensitive than others, but in most cases I think it's not so much a matter of same-day or 24 hour postage, but giving a clear and specific time-frame up front, and sticking to it. Although I also think longer than 2 business days can be a turn-off.
Gallery images can be the key in some categories - fashion and jewellery particularly. I had something listed recently that was up for a while and no takers, with a photo that looked great large, but made the item fairly indiscernable as the gallery pic. I changed it recently to a much better picture that showed less of the item but in more detail, and had a sale in a few days.
One thing I tried recently was to add a custom page to my store, with plans of more to follow, that highlight my knowledge and experience in a way that also benefits customers (potential or otherwise). A recent (informal) survey I saw asked people what is the most important aspect of customer service? The top answer was Servers who know their products well, with Servers who have a friendly and casual manner coming in second and fast service third (out of 6 possible answers, those three got 3487, 2129 and 1505 votes respectively, while things like additional offers and 'any upsell' garnered at most a vote of 242. "Upsell" was the lowest with 128 votes - you could only choose one answer, btw, so roughly 45% of respondents think product knowledge is the most important aspect of customer service, which you can demonstrate in descriptions).
Believe it or not, I also saw research results that there's more to the effectiveness of the old $19.99 price. That is, odd numbers are actually more trusted on a subconscious level than round numbers, like $20.00. The theory is, round numbers appear more casual and arbitrary, whereas a price of say $19.87 gives the impression that more thought was put into the pricing of the item (which in turn gives the impression of more care/greater product knowledge). Interesting stuff. 🙂
The main thing is that while there's some basic recommendations for any seller that will give them a good start, there's no tried and true forumla that's going to work for everything or everybody. Free postage works for some, fails miserably for others. When I start thinking about what might help my sales, I have to be honest and say I rarely think about what other sellers do, mostly because there's thousands of different strategies and I'd never get any sleep if I tried them all - plus it would make me look like a seller with multiple personalities. :^O
I think about things I like as a buyer, and try to come up with different ways to incorporate, improve, or highlight that aspect.
