The most important rule in regard to spacing and margins is to keep every element in the layout separate, i.e. icons, texts and components should not overlap unless otherwise defined.
The margin in the Application Area must be defined so that the title text and list area start, visually speaking, at the same vertical line on the left-hand side.
The size of the margins depends on the view and on the layout. The margins are measured from the Application Area frame or Indicator Area frame (or dialog frame) to the text, bitmap or another control in the Application Area.
In the normal list views and dialogs, the margin is 20 pixels wide. The top margin is measured from the first text line or topmost control to the title bar. It is at least 2 pixels wide. Also, the bottom margin is a minimum of 2 pixels. Text or a bitmap should never touch the display edges. Also top and bottom margins should be somehow equal.
In editors, the margin is 10 pixels wide.
In windows and tables, the margin between the table border frame and the text or bitmap is at least 4 pixels wide at the sides. The space between icon and text should be 4 pixels.
The space between text columns should be at least 10 pixels.