I'm trying to get my computer to use the correct resolution. For that I need to specify the horizontal and vertical sync values in the configuration file (xorg.conf):

Section "Monitor"  

  Identifier     "Monitor0"  

  VendorName     "Unknown"  

  ModelName      "CRT-0"  

  HorizSync       31.0 - 81.0  

  VertRefresh     56.0 - 76.0  

  Option         "DPMS"  

EndSection

Let's say these values for HorizSync and VertRefresh are somehow wrong for my monitor.

Where do I find the correct values?

Note: This is a "dummy" question -- with the help from the chat, I already found part of the answer, and I am now going to add my own answer to document a solution that is hopefully universal.