The Preferences for Google Earth are fairly easy to test and understand their functions.
The Preferences are organized into 5 tabs. Here are some helpful changes you may want to make.
3D View - Change Lat/Long format, distance units, switch between 3D Imagery and User generated 3D buildings
Cache - Clearing caches to improve performance
Touring - Tour recording settings
Navigation - Fly-to speed
General - Language settings (PC)
You can explore the options and always restore defaults once you are finished.