If you aren't already aware of this, you should know that the words included in your auction title are what get indexed into eBay's search engine. Very simply, this means that when anybody performs a search on eBay the words that are in your auction title are what determine whether or not your listing will appear in the search results. Search engines work by searching for the specific keywords that a person enters into it. If your auction title doesn't contain those specific keywords, then it won't show up in the search results. And if your auction doesn't show up in the search results, it's very unlikely that it will get any bids.

Keywords:

First and foremost, include as many of the keywords and key phrases as you can that you believe potential buyers will be searching for. A good exercise to help you out with this is to write down as many of the keywords and key phrases that you think anybody looking to buy your item might search for. When you've got a good list, rank them in order of importance. For example, if I were to try and sell a microwave oven, I would probably consider what the item is (microwave) and the manufacturer and model number among the most important keywords, whereas with the phrase "really great microwave" doesn't tell a potential buyer much.
What you don't want to do is load up your auction title with a jumbling of keywords that doesn't make sense. Make sure your title reads well first. If you have room, include any additional keywords at the end of your title. Make sure your title uses the important words first. What it is, manufacturer and model name/number.

For example,

Microwave Oven GE Express 4302 turntable touch keypad

is better…than this:

4302 oven small express turntable microwave

That jumble of keywords might get your listing to show up in more search results, but you'll receive far fewer page views because nobody can understand what it is your selling, especially if they are just skimming through the listings. The key is to think if you were looking to buy the item you're selling, what would you search for? When you look through the search listings for a particular product, what title would you be most likely to click on? You allowed to enter 80 characters in your auction title. Try not to waste it with characters or words that nobody will ever search for, such as "GREAT". You want to use everyone of those 80 characters if possible.
Here's a handy tool. It's a keyword research tool at: http://www.keyworddiscovery.com/search.html By entering a keyword into the Keyword Discovery search tool, you'll be presented with several related keyword phrases. What makes this tool so great is that it will tell you the popularity of a specific keyword and it also gives you similar words people search for that you might not have thought of.
Don't keyword spam:
One thing you want to avoid is using keywords that you think will drive traffic to your auction, but don't actually describe the item you're selling. This is considered "keyword spamming" and can get your auction removed by eBay. Think about it, don't you hate it when you search for say a “microwave oven” and get listings for “electric range” because people spammed their listings with “works as fast as microwave oven”. It's not going to help and can get your listing yanked by eBay.

West Coast Trading Provides this article for free as a help for people interested in selling on eBay. We make no guarrentees or endorsements of it's content.