Thank you! Oh boy for bgs...
1. Perspective lines are great, but dont feel as if every small little detail needs to strictly adhere to it nor does everything have to be 100% to the T accurate.
2. Add lottsa organic detail, things that aren't rigid and in place ex: books scattered around, paintings/posters that aren't perfectly straight, random little wires running across floors or ceilings are a go-to of mine
3. Foreground elements are great for establishing depth and are usually the darkest (or lightest) object
4. I love having one more strong source of light that highlights the central focus. I often just stick with 1 main one cause I like the dramatics of it