As a pediatric occupational therapist, scissor use is something I assess but also something I teach.  And I teach it early.  I also teach safety early, and teach it with a focus on early success.

What makes it easier to teach children to cut with scissors?

1. Good timing.  Typically-developing children have the visual-motor skills to start snipping with scissors at 24 months.  YUP; that early.  What they don’t have is safety awareness and the ability to select what they should be using.  To teach scissor skills this early, you have to know about fine motor development, child behavior, learning skills, and have access to the right tools.  If a child is unable to attend to your demonstration, unwilling to tolerate assistance of any kind, or unable to use both hands at midline, then 24 months of age is too soon.
2. Good tools.  My long-time readers know that I use only one type of scissor until a child is 4 or 5:  Lakeshore Scissors for Toddlers That Only Cut the Paper, Not the Toddler  Nothing derails training like needing a bandage!  In addition to the right scissors, beginning to cut is helped when the paper is a bit stiff.  The cheap printer paper most teachers and even therapists use to make copies of cutting sheets is difficult to cut.  We don’t experience it as difficult, because adults have better graded grasp.  We can control the scissor more easily as well.  Young children do much better with card stock or at least high-quality printer paper.  Try getting the administration to pay for it, though.  But if you want success, use the right tools.  My private clients learn using the Kumon “LET’s Cut Paper” series of books, or “Paper Playtime”.  Read more about these excellent books here: Kumon Learn to Cut Books: Paper Truly Worth Snipping Up   . 
3. Good demonstration.  Some children watch every move you make.  Others are completely oblivious.  Most are somewhere in the middle.  But learning to cut isn’t intuitive.  Not any more intuitive than changing the air filter in your car is.  Could you learn to do it?  Sure, but it would really help if you could watch someone before you tried it.  I make sure that a child is able to observe me, and being that close to a scissor is another reason to use Lakeshore’s brand of safety scissor.  If a child grabs my hand or my scissor, I might not be happy about it, but the will not be injured.  If they ONLY watch me the first or second time I use a scissor in front of a child, that is just fine.  Some kids are risk-averse, and pushing them to try isn’t smart.  The next time I bring the scissors out, they may be more eager to try to use them, and they will have some information stored away about how they work.
4. Good experiences.  Learning should be fun.  Play should be fun.  Learning to use scissors should be play, not work.  Make it fun.  I will demonstrate cutting on a page that results in something fun to play with.  The “Let’s Cut Paper” books make some cut things.  Another thing that is fun is cutting pieces of paper that fall to the table.  I am doing telehealth during the pandemic, so I am teaching parents to cut 1/2-inch strips of paper and have kids cut across the paper.  They joy in a child’s face when they snip across the strip is wonderful.  It isn’t the same as snipping on the side of the page.  You need to make it fun, or it isn’t going to work.