It all depends how much time and effort you are able to devote. Obviously reading the manual helps, playing with the controls and menus helps a lot, going back and reading the manual again and making sure you understand every page helps a bit more, playing with the camera a lot more and asking yourself "how do I do 'xxx'" helps even more. Get the picture?
Pretty obvious stuff and you didn't need me to tell you the above. However, a good trick is to repeat the process after 24 hours and then again at least once a week for a few weeks. It's a standard revision technique applicable for all learning and is designed to reinforce long term recall. In the process, all those hours of playing with the camera condition the muscle memory.
Mind you, automatic modes are nicest.