Re: turning the back foot when steping in with the right
Not sure if this is what you're referring to but here's how I was taught (it works).
Throw a 1-2 like you normally would, but instead of taking the usual little steps you lunge in with the jab and do your pivot for the right hand in midair. You land with your body and foot already rotated. It's kind of a long-range 1-2. I like to drop it to the body sometimes as well.
It's difficult to explain but 123ko's avatar ^is pretty similar. That's (roughly) the position you should be in when your back foot hits the ground.