Naturally, you will have products with better conversion rates than others and you should use them to get more sales. How? Push them forward to capture as many conversions as possible.
How to see the products with highest conversion rate?
Head over to the Product Reports tab.
There's a list of all products, in order of views they gained in the selected period (change period from the top right dropdown menu).
To see which are the products that sold the best, change the top button to Compare products by purchases.
By clicking on Details for each product, you'll see their individual conversion rate.
Using this information about your most convertible products, you can boost on-site conversions by doing some of the following:
putting them first on the category pages
featuring them on the home page
using them in ads
showing them as related products for cross-sells when possible
In short: if you increase visitor exposure to these products, you'll get higher overall conversion rate.