Shopper goes somewhere and can easily find lots of products that closely match the thing he wants to buy.
Shopper filters all the 'close matches', learning, refining and narrowing in.
Shopper chooses 'The One' from a page of many choices
Click. Shopper is on the page where he can buy the exact one that he just chose.
Click. Checkout. Success.
That workflow is ideal for the shopper and great for the seller, too.
So now take a look at the product page on your store.
A confident product page is one that declares 'Here it is. Perfect. Buy this one.' This 'confident' page will have lots of white space, a dominant 'buy now' button and only information that reinforces 'this is the one' (things like 'in stock' and 'ship this free' and 'BillMeLater').
The opposite is a page that shrieks of 'You probably won't want this one, so let me show you some other things I sell. Here, look at related products. Look at all my other categories of things to buy. I won't show you shipping costs, since you almost certainly aren't going to buy anyway. Here, just in case I haven't talked you out of it - see how nobody has written any reviews?'
Here's our tip. Treat your product detail page as though the shopper is 99% certain to go ahead and buy exactly this product from you. Take all distractions and alternatives off your page. Everything that you leave on the page should make it MORE LIKELY THAT THE SHOPPER WILL BUY THIS EXACT PRODUCT. Be bold.