I was taught crocheting at age 4 by my grandmother, and sewing by my mother at the same age. In the almost (but not quite!) 50 years since, I have made a living from and had a lot of joy out of sewing, crocheting, crafts like jewelry and beading and whatever caught my fancy.
But I could never get the hang of knitting. I wanted to knit. I even longed to knit. I loved the look of knitting. But it just wouldn't stick in my brain, even though I knew how to stitch a knit and a purl. Projects would live on the needles for about two years, and eventually I'd throw it out.
This last New Year's, though, in the middle of a terrible cold snap in the UK, I wanted a very long, very warm, preferably merino wool scarf, and when I found a "weekend" cabled scarf and then realized how far available yarns had come (I had been trying to learn knitting in the days of basically five kinds of yarn and one or two kinds of needles), I realized that I could knit what I wanted on bulky merino yarns and large, beautifully made needles that helped instead of hindered, and get it done really quickly.
So I did. Now my family thinks I'm obsessed, and I guess I am! I LOVE knitting, finally, after all these years!
Previously, I'd always tried to teach myself on acrylic yarns and cheap needles, figuring that I shouldn't waste money on something I was just learning. Working on lovely fiber and nice tools on New Year's Eve, I suddenly had this epiphany: I am a total tool and fiber snob. When I sew, I work mainly with nice fabrics in beautiful fibers (I specialized in silk wedding gowns), and with the best tools I can afford. The same goes with every craft I've ever done.
What the heck, I realized, had I been thinking?! No wonder it never stuck: I had tried working on projects that I felt were boring, in fibers I normally wouldn't touch with a ten foot pole, on tools that were so basic I might as well have made them myself out of twigs...if twigs were made of plastic.
So now when people ask me about learning a craft (most recently, of course, since I've been taking knitting with me everywhere, knitting), I tell them: don't work on projects that you don't love. Only choose projects and materials and tools that you love. If you love the project and materials, it will carry you through the boring and/or frustrating bits.
If you love an inexpensive acrylic yarn, great! If you love your plastic bargain-store needles, FABULOUS! I'm not saying you have to be a tool or fiber snob like me. But love what you're using, in a project that you adore.
It's the only thing that gets me through the umpteenth frog to go back and fix the row with bad tension.
Hope that might help you!