This post by -pkh- on the 'Nose-in hard to master' (or something like that) thread, helped me alot:
ORIGINAL: -pkh-
Practice until you get so that nose-in is "automatic" for you in the sim (i.e. you don't have to think about the controls very much), then turn the wind on in your sim, say 10mph wind with 20mph gusts, and practice that until that's automatic. Once you get that, you should be pretty well prepared... although nerves can get the better of you sometimes when you're doing it in real life! Without wind, you can usually provide the wrong control input and correct it without getting into trouble, but when it's gusty, you have to provide the correct control input immediately, and an incorrect control input can get you into trouble quickly. Practicing until it's automatic for you eliminates the occasional control mixup, and practicing with wind turned on gets you used to fighting the wind, like you'll have to do in real life.
Just a word about going from tail-in to learning side-in and nose-in...
I found that when I practiced one position at a time, I was simply memorizing a direct mapping of left/right and front/back on my controller to the left/right and front/back movement of the heli for each of these positions. This is not what you ultimately want to learn! What you do want to learn is how to get that "sitting in the cockpit" perspective on the controls, so you can control the heli in any position, and transition smoothly between the positions while maintaining control. Two things that I practiced in the sim that really helped me get this perspective were 1) slowly rotating in place, i.e. hovering and rotating 360 degrees very slowly, and 2) start with tail-in hover, fly forward slowly, and then slowly turn and come back around towards you, nose-in. Both of these exercises helped me to watch the cockpit and move my control perspective with the heli, and not simply memorize that left/right and forward/backward are reversed for nose-in!