1. Picture Style set to Portrait.
2. Contrast set to minimum.
3. Saturation set to minimum.
4. Gradation set to Auto.
Something else I do with my Olympus E-M5 is use the Gradation control. The Gradation control is a curves tool that has 4 settings: Low Key, High Key, Normal, and Auto. Setting it to Low Key further reduces contrast. This is what it says in the manual about the Auto setting:
Divides the image into detailed regions and adjusts the brightness separately for each region. This is effective for images with areas of large contrast in which the whites appear too bright or the blacks appear too dark.
Rather than use the Low Key setting I have mine set to Auto.
I also set Saturation to the minimum. This helps a tiny bit in reducing blowouts in the EVF and also makes the histogram and highlight/shadows blinkies a bit more accurate reflection of what is in the raw file.
Since I shoot raw I don't care what the settings do to a jpeg, I just want the EVF to be as useful as possible.