Is there any way to avoid square boobs after a lift? What makes you more or less likely to have this effect?

I recommend a new technique called The Horndeski
Method™.The breast tissue is reshaped
creating upper pole fullness, elevated higher on the chest wall and more medial
to increase your cleavage.This
technique avoids the ugly vertical scars associated with the traditional
technique, maintains nipple sensation and the ability to breast feed.Best Wishes,Gary Horndeski, M.D.

Not everybody ends up with square breasts after breast lift/reduction. It has lot to do with a surgeon performing surgery and a particular technique used. Goal of breast lift surgery is exactly what you want; natural, round and perky breast. However, despite all expertise that your surgeon might have, very soft, saggy breast may end shapeless. Addition of breast implant can in some patients help breast projection and shape.You should have consultation with a board certified plastic surgeon for detailed evaluation and to discus your options. Good luck. 

Start by scheduling a consultation with a board certified plastic surgeon in your area (link below) whose breast lift photos suit your aesthetic. Excellent results are going to depend on the skill and expertise of your surgeon. Best, Dr. Nazarian

There are several techniques for doing breast lift surgery depending on how saggy your breasts are.  Most of these do not result in "square boobs."  I think this would be a bigger risk with the traditional anchor-type breast lift procedure if the skin under the breast isn't tightened enough.  I really haven't had a problem with "square boobs" in my practice.  I would suggest that you schedule an appointment with a board-certified plastic surgeon who can examine you in person in order to determine the best type of breast lift procedure for you. 

Thank you for your question.  Depending on the technique of breast lifting employed, certain surgical steps must be taken in order to yield the best, most natural results.  This will be determined based on the severity of sagging that a patient displays, their skin quality, and the possible placement of implants at the time of surgery.  In order to best communicate your desired results, reach out to ASPS board certified surgeons in your area for an in-person evaluation and discussion.