eBay's Markdown Manager is a wonderful way to increase your eBay sales. With this tool, you can put all your eBay fixed price items (or just some of your items) on sale -- at the percentage off that you choose.
When sales are sluggish, I have found that Markdown Manager ignites them ... it seems to bring new attention, since the prices are different from before. And buyers seem to be drawn to a percentage off sale.
To find Markdown Manager, go to My eBay, then Account (top of screen), then Marketing Tools. You'll find Markdown Manager on the Marketing Tools page.
To use Markdown Manager, sign in to the page. First you will want to choose a sale title. This is just for your reference, so it can be anything, i.e. Books 10% Off.
Then you will need to choose a start and end date for your sale. In my experience, a good sale period is 2 - 7 days. I have not had success with sales less than 1 day or more than 7 days.
Then you can choose a percentage off. This is up to you -- 5%, 10%, 15%, etc. I generally have deeper sales (i.e. 20% - 25%) for 2 days, and smaller sales (5% - 10%) for 7 days. But experiment with this, and see what works for you.
Then you can choose to put one category of your listings (i.e. Books, Sewing Patterns, Postcards, etc.) on sale, put your entire store on sale, or you can choose items selectively using any criteria using the link "Select listings individually." I love this feature, and usually select items this way -- i.e. items under $8, or ephemera only, or items over $20, etc.
I am a great fan of Markdown Manager and Best Offer (an upcoming blog post!), and find both these eBay tools are great for generating sales. I hope this is helpful for you too!