Increase or Decrease Text Size by 1 Point

To increase the text size by 1 point, select the text and press Control + ] (Right Square Bracket).
To decrease the text size by 1 point, select the text and press Control + [ (Left Square Bracket).
The square brackets are to the right of the letter P on a standard keyboard.
Keep pressing the shortcut to increase/decrease by 1 point, until you reach the required size.
As a guide for point size, 72 point is 1 inch high letters.