You should be able to change the default margins in Normal.dotm with the following steps:
- Create a new document.
- Choose Layout>Margins>Custom Margins and set the margin measurements.
- Click on the Set as Default button. This copies the margin settings to Normal.dotm.
To change a style default, follow these steps:
- Create a new document.
- Open the Styles Pane (Ctrl + Shift + Alt + s)
- Click on the Manage Styles button at the bottom of the Styles Pane
- Select the No Spacing style, then click on the Modify button.
- In the Modify Styles dialog, click on the option New documents based on this template. This saves the changes to Normal.dotm.
- Using the Format dropdown, change the characteristics of the style. OK out when you're finished.