If you know your eBay competition and how they conduct their business you will have a good idea on what to do in your own auction and combine all the best bits of your research to make yourself mega successful.  Below are some steps you can take to find your competition and how they conduct their business:

Step 1: Identifying Competitors: Do keyword searches that people might use to look for your items.  Look the results eBay pulls up as these are your competitors.  Look at the relevant eBay PULSE page to see who has the Largest Stores in your category (http://pulse.ebay.com/).

Step 2: Now you have found your competitors - write down their eBay user names. Then go to Advanced search, select the search 'completed listings' box and enter up to 10 of their names in the “From specific sellers (enter sellers' user Ids)” to bring up their auctions (or do it one seller at a time if you prefer).  Specify that results are sorted ny 'Highest price first'.

Step 3: Analysis time!
Look at the items that are generating the most bids and the most money.  How does your price compare and offering compare?

Think about:
The category they are listing in.  Is it more suitable then the one you are listing in?

The auction format: auction format or Buy it now?  How may days auctions are running and time auction ends.

What keywords are they using in their title, order of the words, use of CAPITALS, is it bold?

Are they offering a Buy it Now price? If not what is their minimum bid? Do they offer both options or a Best Offer price?

Their photo (or ebook cover if that is more relevant). Does it stand out?  How is it staged?

Their headline and copy: What benefits are they highlighting and keywords used in headline.  How are they writing their salescopy?  Using traditional methods, experimental, injecting personality.  Do they answer potential customer questions?

What are their shipping policies, refund policies, who do they ship to?

What is their About Me page or MyWorld Page or their store like?  Do they have one, what is on it? What else do they sell and promote? What selling tools do they use like do they have a store newsletter?

How many reviews and guides have they written to help build customer relationships?

What is their feedback rating like?

You may want to even buy a product from one of your competitors to see what their selling process is like and how they go about it.

STEP 4: Now you will want take all the best bits you have learned and implement them in your own auctions, see what you can do better, what a competitive edge you might after combining all the best strategies you have learnt.  A word of warning though, never copy them directly but I'm sure you know that anyway.