Hello Johannes,
If you look through the various policy templates provided with 5.7 you will find many examples for various use cases that adjust each of the areas (except for Manage Display Settings) you list. These should get you started, but ultimately you just need to understand the service level agreements and requirements of the managed environment more than anything else - that's really the "best practice" when configuring policies.
For example, start with the "Production Environment" template for your production systems and then adjust it as needed to meet your own organizations' SLAs.
Now, for the "Manage Display Settings" that really is a bit different as this only adjust the output display of views, not the calculations. You can tweak this on the fly as needed.