Loads of great advice given so far.
Remember that this is going to be the hardest thing about your flying course. And if like so many you are on an R22 then if you can hover a Robbie you can hover anything. If you are on another 2 seater then you can hover anything (including the robbie but not quite as prettily than you can hover your first type). If you are learning on a bigger type.... you lucky........!
Next time go out and don't think about the hover - if you are thinking about what inputs to make, then it is too late. Relax, keep your eyes moving (ie don't fixate on anything) and don't give a stuff if you can't do it. One day you will and you won't know why. Oh and if you take longer than average, don't worry you will be better than average at something else.
Happy flying