Space between paragraphs should be added using Space Before or Space After, not an empty paragraph.
By "blank spaces", I'm guessing you mean non-numbered blank lines.
You can add a forced line break to get non-numbered/bulleted lines, but that doesn't release the bullet/numbering style.
You can set a keyboard shortcut for styles:
To add a keyboard shortcut, position the insertion point in the Shortcut box, and make sure that Num Lock is turned on. Then hold down any combination of Shift, Alt, and Ctrl (Windows), or Shift, Option, and Command (Mac OS), and press a number on the numeric keypad. You cannot use letters or non-keypad numbers for defining style shortcuts. If your keyboard does not have a Num Lock key, you cannot add keyboard shortcuts to styles.