If you're using the same styles over and over again in the same document, it's more convenient to set a hotkey that you can press to automatically invoke the style.

1. From the Style toolbar drop-down, select "More..."
2. Mouse over a style and click the drop-down arrow that appears, then select "Modify"
3. Click the "Format" button menu and select "Shortcut key" from the drop-down menu
4. Press a new shortcut key and hit "Assign"