As all the other guys have said it is just lots of practice.
I have been riding for 7 months now and i have just got my head round most of the basics.
What really helped me was a DVD i got called 'Mastering the art of trials by Ryan Leech' - it brilliant, break downs or every technique beginner to advanced,
Mastering the art of trials - All the sections of the DVD are on YouTube
Hope it helps.