I do a few things, some of which others have already commented on:
1. My Outlook is set to open in Calendar view with Tasks in the pane on the right.
2. I open the Mail in a separate window.
3. I have turned the new email notification sound and visual cue off.
4. I have set up email rules to route much of the non-actionable email I get straight to the trash or to email folders for later review in batches. This means stuff that is left in the Inbox is usually what I need to care about so I don't feel bad when I periodically check and process it.
5. Email sent only to me is coloured purple and email from my boss is green so that they both stand out. This helps with the processing priority.
Another thing you can do which a colleague of mine swears by is to change the frequency Outlook checks for new mail to something like every hour or greater. It won't take your mind long to realise there's no point checking the Inbox because nothing new will be there!
Hope this helps.