My little one is only 6 weeks old, so I won't be much help, but so far we've done the newborn hug hold and the hug hold...she loves both and once she can hold her head up reliably then we'll move on to the other positions. Good luck!
The more you do it the better. I found the book that comes with it very usefull. We used ours daily for a very long time. It's almost too hot here for the jersey fabric now though. We really love ours though! Good luck!
I think it took a couple of weeks for me to really get good at tying it on just right. Also, I became less nervous so I was able to adjust the wrap while my baby was in it. Before that, I would sometimes tie it too lose and my baby was sagging.