keep practicing you'll get the hang of it. i don't remember how long it took for me to hover reasonably well, but it seemed to take forever.
i found looking at something far away helped me be more stable, my instructor was always yelling at me to not look at the ground.
also try and relax, i found after my first few lessons my wrist would be sore from holding the cyclic so tight.
keep control movements to a minimum, it should take very little movement of the cyclic to hover and if you are constantly moving the collective or the pedals it gets a lot more complex.
also hovering into the wind is a lot easier, especially the stronger the wind is.
anyway hope that helps, i only have 50 hours now so others with more experience may be able to add more advice. just don't give up, once you get the hang of it it is a lot of fun