Assuming she knows how to use a sewing machine, I think teaching rotary cutting would be the first lesson. Strip piecing would be the second lesson. Pressing would be the third lesson.
I'd probably pick out a few coordinating fabrics from my stash to use, and start with a rail fence block. Depending on how quickly she picks up on it, the two of you might be able to rotary cut, strip piece, press, and cut out enough rail fence blocks in an evening to have a crib quilt started. Not everyone would be able to learn all of this in one evening, though. You might have to just figure on one lesson per evening spent together.