Skelgarer’s steps are fine for finding latency issues to the Home Server, but the problems everyone runs into is based more around connections to the World Server. I find this is a better way to use WinMTR to pinpoint latency issues in specific zones.
https://us.forums.blizzard.com/en/wow/t/using-winmtr-to-troubleshoot-lag-issues-inside-sl-dungeonsraids/868417