On mobile, there isn’t currently no visual feedback when a product is added to the cart.
A simple solution would be to display a toast notification.
But I noticed you can stick the mini cart (both on desktop and on mobile), placing it in the left sidebar enabling the appropriate option. The only issue is that the minicart is too big on phone screens (I’m testing on iPhone 5).
My idea is to develop a mobile version of this minicart, sticky to the footer, tall just 50px, displaiyng only price and number of items, with a “View cart” button.
Example:
Page content
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------------------------ <---- sticky footer band
€ 20.00 (2) View Cart <---- sticky footer band
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<—- sticky footer band