Here's a trick I came up with when I was learning to hover nose-in: "Just follow the heli with your stick."
Confused? Here's the explanation. Start with a tail in hover, then just rotate it into the nose in position. The objective is to keep the heli perfectly still in front of you in this position. If it starts to drift towards you, it means the nose is dipping. The correct counter for that is to pull down on the elevator stick to make it move back (in this case away from you). The reverse is the same. If it starts to drift backwards away from you, it means the tail is dipping. The counter for that is to push the nose down by pushing the elevator forward to make the heli move forward (in this case towards you.) Got the logic? The same applies to the left and right.
So, basically, the counter for any drift is to follow the heli with your stick. It's the same even if you have to apply it diagonally. I know it's counter-intuitive at first, but if you just follow the rules, you'll get a comfortable hover in no time.
After a while, it all becomes automatic to you and you won't need to use this trick anymore. But in the mean time, for those who are just starting, I hope this helps. Good luck! Let me know how it goes. =)