To see if you have qualified for any new Disciplines, visit your Book of War under "Player>Books>War" and click "Unlock Disciplines".
Disciplines that are faded out have not yet been learned. Simply hover your mouse over them to view the conditions needed to unlock them.
A creature can only utilize a Discipline if it is the correct type. The only exception to this are users with the settings "None" or "Special". They can utilize glove disciplines.
To view another player's Book of War, go to their status screen and click "Book of War".