Because Outlooks emphasis on today is so minimal, I would like to grey out items in the past.
I found a similar solution here: "Highlighting the Current Day in Outlook 2013 Calendar", but I don't see the (advanced) conditions in Outlook to simply grey out all items with an end date before today.
How can I grey out items/days in the past?
Just like in the solution you've mentioned, use Contidional Formatting for your Calendar. But this time on the Filter's "Advanced" tab, select Field -> All Appointment fields -> End. Specify on or before Condition and today (without quotes) as a Value. Don't forget to add this criteria with "Add to List" button.
I found a different way around this. Not being satisfied with the conditional formatting solution (- owing to the failure in recurring appointments not being affected), I tried just changing the calendar colour away from the default. (View>Color). Picking something more garish such as the bright blue, or pink, makes the subtle emphasis on today contrast more starkly with the grey background, so it's more effective.
Now I just have to put up with a fluorescent calendar .
Also, moving my Reading Pane (View>Layout>Reading pane) to the Righthand side and increasing its size, so that the day columns are narrower, makes it easier to differentiate them. (This is more of an issue on a large monitor than a smaller one, i.e. laptop).
