I know it was mentioned awhile ago, but I wanted to make a comment in regard to listing sizes in auction titles. I've found that my auction listings that DON'T have a size in the title have gotten far more views and watchers than those with the size. I'm assuming it's because everyone hopes that it is their size and are willing to click to find out. I still list the size in the drop down menu, so it can be filtered, but I'm happy if more eyes are viewing the auction as it gets people to reconsider it.
It's probably obvious to everyone, but I thought I'd also mention this: many people filter by price and the price points can make a huge difference in who sees your auction. I recently listed a pair of shoes several times in a row starting at €75. They didn't sell and when they finally hit an opening bid of €49,99, they got a lot of immediate attention. They ended up selling at my first opening bid.
I don't have a lot of hard numbers to back things up like some of you guys that deal in volume, but it's becoming worthwhile for me to list something at €49.99 rather than €59.99 if it sells quicker and gets more attention.
That is some solid/sound advices!