Because DCL list boxes cannot be scrolled horizontally, the width of the list box should accommodate the longest item in the list. Provide a label (or a text tile) to explain the contents of the list box, unless the list box is the main tile in the dialog box. In that case the dialog box's label might be sufficientâ€”although you must give the list box a label if you want users to be able to move to that list box by using a mnemonic.
Alphabetize the items in the list unless you have a logical reason to organize them in some other way. If the length of the list is fixed and short, consider using a radio column instead of a list box.