I am a big fan of using keyboard shortcuts while working on computers
To see if a keyboard shortcut already exists for a function in Premiere Pro, hold the cursor/arrow over the function key until a little tag appears describing what the function is and any predetermined shortcuts for it. For example, hovering over the play button for a few seconds will cause a little bubble that reads “Play-Stop Toggle (Space)”.
If the function key you want to have a shortcut for does not seem to have been given one, go to Edit > Keyboard Customization… and you can set a shortcut for any function in Premiere. A particularly helpful one I have set is in Keyboard Customizations… > Marker > Set Clip Marker > In (and,) Out.