There is nothing more frustrating to an E-Commerce website owner that watching potential buyers leak out of the bucket that is their shopping cart. The industry average is 65%, which means that the average shopping cart only converts 35% of the time. I would call that a leaky bucket!
Google analytics has a really useful tool called the Goal Funnel, which displays bail rates at every step of your conversion funnel. You start by defining your goal funnel, which in most cases starts with the view cart page, and then proceeds to the success page. By defining each step in the conversion funnel, you can visually see which steps of the conversion funnel have the highest drop off rates, and then work to lower the bail rate on each step.
For example here is the first step of the conversion funnel:
As you can see, only 46% go on to the next step. Lowering the bail rate on this page will have a dramatic effect on the overall conversion rate, as this is the first step.
Our new version of the checkout page has 79% going on to the next step, which means we kept 77 more visitors in the conversion funnel, which has a huge effect on sales.
Keep making these kinds of improvements at each step of the funnel, reducing bail rates at every step of your conversion funnel and watch your revenue grow by significant amounts.