I left all my best items in unsold recently and gave the slowest items a go. I sold quite a few things that have been listed for about the same time as your manual.

I don't know how ebay make things invisible but it really does seem as though they hide a lot of stuff and only show it when you haven't got all your listings up! I sold too many 'slow' items for it to be coincidence!

I also find some of my best items are slow to sell but when I put them on facebook they sell straight away, exactly as they should do on ebay.