First of all, what does a long time mean? Does it mean a few weeks or does it mean a few months?
Second, make sure you learn "Instant Replay" [first.
Third. Just stick with it. Do it over and over and over and over and over and over, until you really get a feel for the amount of pressure you need. It is extremely knack-y. Trust me, blunt repetition of it will work, but make sure that within the repetition you are making minute changes and really trying to get the movements sunk into your muscle memory.
It took me half a year to learn. Maybe it'll take you longer, maybe not. But trust me, just stick with it.
Good luck!