get Google Plus One module for your Drupal
http://drupal.org/project/google_plusone
/admin/build/modules
enable
Google Plus One +1
/admin/settings/google-plusone
Display the button on these content types:
enable
Page
Display the button in these view modes::
enable
Full node
Include count?:
No
Size:
select
Small (15px)
Optional wrapper with CSS:
margin: 4px 4px 14px 14px;float:right
/admin/user/permissions
google_plusone module
view google plusone
enable
anonymous user
authenticated user