Positioning
Here is a snippet of an interview with Craig Joubert, a former international, and Olympic, referee from South Africa. Here he talks about an intentional decision he made with regards to his positioning and running lines. He strove to give himself consistent vantages of the breakdown (enabling him to make consistent and clear calls) as well as focusing on ball-in-line running. This video is courtesy of Advantage Rugby Referees.
Here is another video from Advantage Rugby Referees that was used as a part of the D1A league prep for Spring 2024. It covers more than just positioning and is worth watching in full. The positioning portion begins at 26:26.