You should practice playing these at the keyboard
until you can produce any given triad without hesitation. The
objective is to conceive of each as a unit, rather than as
individual notes. For example, as you read this passage, you
are not conscious of individual letters in each word. You do
not think "y-o-u," but, rather, "you." If
you can play the triads quickly at the keyboard, it will reinforce
your mental ability to identify and write them as well.