Selling on eBay is no different than in Retail! You have to "sell" your items!
The reason many get a poor price for items is they dont do the item justice, Poor photos, poor description will get a poor price!
If you want to sell your item above the many others the same, and for a good price, "sell it" better than the rest! Take pictures with enough clarity you would want to see, and enough accurate details about it you would want to know about it.
Dont assume the buyer knows its value from new or its current condition.
If it cost £30 new and its hardly been used, dont put it up for 99p and not tell the "viewers" its RRP value.
Put the new price, then people would pay £10 and still have got it for a 3rd of the cost of a new one.
Dont put an item up for 99p to save 12p listing fee if you want a £5 for it! Pay the pence listing fee and put it on for a reasonable, but not too high price.