Your password can be changed by first navigating to your Account Settings, and then clicking on the "Change Password" button.
In order to change your password you must:
be signed-in, and
know your current password
or
use the Forgot My Password page
Best passwords usually:
are 16 characters or longer
contain numbers
include symbols such as !,@,#,$,%,^,&,*,(,) and punctuation
are not words found in the dictionary
have lower and upper case letters
are not the word password, the numbers 12345, or similar