Dynamics 365 - Consult TracingService logs

Steps to follow if you want to view log made by plugins with TracingService. Example:
serviceContext.TracingService.Trace("Test");

1. Navigate to Settings > Administration > System Settings.
2. Click Customization tab and locate the drop-down “Enable logging to plug-in trace log” and select “Exceptions” or “All” depending on what you need. Click OK.
3. Run the plugin.
4. Navigating to Settings > Plug-in Trace Log.

Dynamics 365 - Debug Plugin using Plugin Registration tool

I found this video on the youTube channel Magnifez Technologies

Dynamics 365 - Plugin development step by step

I found this interesting video on YouTube.