How do I change the default font size for reading the body of messages in Mail 6.0? I know that I can use ctrl++, but I want the reading pane to default the body of the message to a larger font without lowering the default resolution.
This is a setting that can be changed in Mail Preferences. Open the dialog box by clicking:
Mail > Preferences (or Cmd + ,) > Fonts & Colors > Message Font > Select...
A dialog box should display with text options for you to customize.