When developing your E-commerce website it is easy to get lost in SEO, SEM, traffic and conversion rates. While all of these are of importance, you should also concentrate on the average e-commerce transaction rate as well. Not giving this any proper thought will have you going out of business because you do have a big customer base. For example, if marketing tool you employ causes you to spend $5 getting a customer to your site and you end up selling a $10 product for $15, the margin you have is zero. On top of this you have your fixed costs to apportion, so in reality you are making a loss. To rectify this you must first of all find a marketing tool that is efficient and justifies what you spending on it and second of all you must employ some techniques to increase the total value of the sale.
Up-sell - At the point of checkout is a great place to up-sell and convince the customer to buy something additional items. Generally this means pushing products that compliment the product that the customer has bought. For example, if the customer bought flowers you can offer greeting cards, wine, chocolates, etc at the checkout.

Packages - Offer the product the customer wants to buy, in a package which is appealing to them. The products described in the example above could be packaged together, which makes it more appealing to the customer.

Intelligent offers - Based on what type of product they have placed in their shopping cart, you can suggest products that compliment it or products that other customers have bought along with it. If you have access to the customer’s preferences, then you can combine all three aspects to offer products that have a high chance of being purchased by this customer.

Shipping - By having a minimum amount for free shipping, you can entice the customer to put a few more items in their shopping cart. This is a great way for you to raise your average transaction rate.