Did you know that you’re not limited to the columns you see in your Outlook views? You’re not even limited to the larger list you find in the Field Chooser.
From the view tab, View Settings button, click on the Columns button and New Column to create your own. For example, let’s say in Contacts (People in 2013), you want to add a client number. After clicking on the New Column button, you can choose the field type (numeric, text, etc.) and format (1 decimal, 2 decimal, dd/mm/yy).