To update your personal account settings, log in, then click "My Account" in your user menu (the one with your username at the top) in the left column. You should then be at:
Home » user account » my account

Then, click on the "Edit" tab at the top of the center column to change your settings.

IMPORTANT: Once you're on the Edit tab, please note that there are two preference panes: "Account Settings and "Your Membership." You can find these selections just below the tabs.