You know I'm trying to teach my Wife AND daughter how to knit..
Problem I have is that my daughter is Left handed.. but I'm teaching her right handed Knitting.. I told her to stop and we'd find my parents who know left handed knitting, but she keeps going..
What I did was show them the difference between the knit and purl stich.. so they could SEE what they looked like..
Then on a pair of regular straight needles (size 9 or 10 would work, maybe even 7's) I use a light color, so you can see the stiches, of worsted weight yarn and casted on 10 - 20 stiches (depending on the person). Then I showed them how to do the KNIT stich only.. did a few rows while they watched.. then gave them the needles and graibbed a pair of my own and knitting along side them so if they had questions, I could SHOW them without taking the needles out of thier hands.
The most important part is getting them used to the needles.. only take the needles away, I've found, if you have to..
We will be doing purl stiches probably next week, when the girls say they are ready.
But that's just my experince