Label
Text associated with the checkbox
Default selection
Whether the checkbox is selected or not
Style
Make sure checkbox is unique and stands out from other input options
Clickability
Consider what is clickable to make the checkbox active (text label, container)
States
Radio can be default, active and disabled (see examples below)
Default
Checkbox is visible and unselected
Active
Checkbox has indeed been checked
Disabled
Checkbox state can not be changed