I trained alone most of my lifting career. If you can call it a career.
Anyhow, one thing i really started to like the last 8 mths is not timing my rest periods, its all by feel. I assume you don't time your rest periods but its worth mentioning. For instance, my bench press and OHP i take much less rest between heavy sets then i do deadlifts.
Another thing i started to do a lot since i stopped looking at the clock is visualizing my lifts - with speed. I try to almost snap.
I'm very quiet when i train too. Like a quiet determination. I never listen to music but have the TV going most of the time but its in a different room. But its the room i usually rest in. That could will be a personal preference.