You can control how Outlook starts by using command line switches. While many of the switches are used only when you are having problems with Outlook, including /cleanviews and /cleanreminders, several allow you to do things in Outlook from a command line, such as open a custom form using the /c switch:
outlook.exe /c ipm.contact.​familyaddresses

Or open a new Outlook window to a specific folder:
outlook /select outlook:calendar

One of my favorite tricks is creating shortcuts for new messages preaddressed to specific people that I frequently send messages to. The shortcut's command line accepts the email address, alias or resolvable name and looks like this:
"C:\Program Files\Microsoft Office\root\Office16\​OUTLOOK.EXE" /c ipm.note /m someone@slipstick.com;mary

You can create a Quick Launch or Desktop shortcut that opens a custom form, such as a While you were out phone message form, by replacing ipm.note with the published form name (i.e. ipm.note.wywo). (WYWO sample forms are available at Microsoft Sample Applications)

How to use Command line switches

If you're new to command line switches, you can either use the Start menu, Run command (Windows key + R) or click in the Search box in the taskbar (or click on the Start menu, if you aren't showing the search field) and type the application name (outlook, in this case), a space then the switch. In most cases, you only need "outlook", but outlook.exe or the full path to outlook.exe also work. Tip: if you are using a switch you'll use again, use the Run command as it will add it to the most recently used list. You'll be able to select it from the list instead of retyping it.

Outlook /switch

Then press Enter or click OK to start Outlook.

Occasionally you'll need to use the full path to Outlook, in which case, the command line will look like the following. If the path contains spaces you'll need to use parenthesis.
"C:\Program Files\Microsoft Office\root\Office16\​Outlook.exe" /switch

You'll need to use the full file path if you are creating desktop shortcuts. The default location for the "click to run" versions when Outlook and Windows are both either 32-bit or 64-bit is
C:\Program Files\​Microsoft Office 15\​root\​office15\​outlook.exe

If you are using 32-bit Office on 64-bit windows, the Office applications are in the x86 path:
C:\Program Files (x86)​\Microsoft Office 15\​root\​office15\​outlook.exe

Corporate users with volume licenses will find the Office applications in one of these paths:
C:\Program Files\​Microsoft Office\​office15\outlook.exe
C:\Program Files (x86)\Microsoft Office\​office15\outlook.exe

You'll need to use the full file path if you are creating desktop shortcuts.

For a video tutorial, see Command Line Switches Tutorial

Popular and Useful Switches

These switches work in all versions of Outlook.

All Command Line switches

This table lists all of the switches available for Outlook 2007, 2010, 2013, 2016, 2019, and 365.