Skubana's Analytics module lets you know which of your SKUs are selling the most, and the least. Skubana arrives at this information by analyzing amount of units sold as well as generated revenue. You can break down the report by sales channel.
Armed with this info, you can shift your sales and marketing efforts to your top sellers. You can keep stock of your top sellers on hand, to meet potentially higher demand.
You may choose to drop the poor performers altogether since they are hurting your profit margins. You can then allot the freed-up warehouse space to those SKUs that really make a difference.
If all is not lost with an SKU, since it may be performing well on your other sales channels, you may shift its stock to those channels instead, where chances of the SKU getting sold are higher.