Based on my online shopping experiences, presented with unexpected costs is main reason for me to leave without chekcout.
Sometimes I've just spent the half an hour at online store picking up my clothes. When I approach the checkout the system announces my total, followed by tax, extra hidden will let me down, I might think about other steore without these hidden fees or cancle my order if free shipping is not offered.
Another reason is website crashed or was too slow.
When I was trying to buy my shoes, I got through the ordering process, clicked submit and I came up with a little screen that said 'sorry there's been aliggle glithch in our system,", I have to choose another online store bought the sames shoes instead.
So here is some tips to avoid shopping cart abandonment:
(1) Show Images to customer
Some websites display a tiny photo image in the cart, and shows me a stock photo rather than only text to describe what I am buying, I may wonder if my order is correct. Show me images can confidently quickly to check out.
(2) offer free shipping and avoid registrations
I more likely to shopping with online retails who offer free shipping. So provide free shipping service would be better. Otherwise, cut down the difficult process such as being foced to register when I want to check out as easy way.
(3)Email Recovery
Another way to get me back to the online store to complete my order is throug email. They setup personalized emails that sent to me if I don't complete my purchase.
(4)Ad Retargeting
Retargeting works by keeping track of my visit site and displaying their ads to me. That is a useful way to retarget me to go back shopping , when I saw my previous interesting itesm as ads on another webiste, I would like to accept the ads and might be go back to purchase.