Do you charge for shipping? How careful are you to make sure that there are no surprises in the checkout?
Gone are the days when it is possible to succeed by declaring 'shipping costs will be estimated during checkout'. That's one of the most successful ways to increase your abandonment, not your sales.
Here's our tip. If it's at all possible, reconsider your product prices and try to absorb the cost of shipping, so that you can advertise 'free shipping'.
If you simply can't do that, then at least keep your shoppers fully informed about the 'real cost'.
In your admin console, under Configuration > Settings, look up a setting called "ShowShippingAndTaxEstimate". Set it to Yes and then be very sure to test it and see if it works for you!
You can also use the option in your admin console under Content > Prompts to search for the words 'Get Estimates' (this is the out of box wording on the button) and change it to say something a little more inspiring ...