No. There's no trick to it. They either do, or don't.
They're interested, or not. That's life.
One of my daughter's learned, but after knitting a boatload of by-the-front-door guest slipper booties...and quit.
My college granddaughter learned, did knit an entire scarf (!) and quit.
My almost-the-youngest granddaugther learned to knit a scarf, never finished it, and quit.
I taught them to knit at their request. All 3 of them were very proficient.
But just not interested enough to make time to continue.
Gotta say...the middle daughter has a home and 2 little kids; the oldest granddaughter just graduated from the UW yesterday! and the younger granddaughter is excelling in grade school!
Timing is the key. Maybe later will be better! Maybe not.