I must, I must improve my ........... knitting !!!! A good place to start is with the cast on so I've spent an hour or so on YouTube looking at various methods of casting on. I think the cable cast on for 1x1 rib is my favourite so far and I'll post the link here so it will be easy to find for future reference. Did a small swatch but I think I'd be inclined to use a size larger needles for the first two rows of the main colour yarn and then switch back to the size required.
Another method worth trying is this stretchy long tail method This one is not as neat looking but is much more stretchy. I used a 4.50mm needle and a 2.75mm one for this cast on sample.
Yet another is called very stretchy cast on and I think that with a bit of practise would be a really good method.
OK .. having tried all three methods, THIS is now my favourite - although I do like the look of that first one. As the name implies, this one is very stretchy, and actually quite easy to do once you get the hang of it. Its a quick method when mastered as you're casting on two stitches at a time.
Whew, after all that research, I think I need a drink. Must now go and brew a fresh pot of coffee.