When tweaking background sound effects in post, the aim is to find a balance that doesn't over-power the spoken narrative. Here are some rules to keep in mind.

First off, keep a "quiet" layer for background ambiance to create a consistent sonic space – usually 30-40 dB lower than the dialogue. Aim to maintain an LDR (Low-Dynamic-Range) meter read in this layer of -25 dB to -15 dB to prevent over-compression. Don't overdo it with music or sound effects that demand the listener's attention, and avoid using them as a crutch for a weak narrative.

Next, use EQ and compression strategically on your sound effects and music to ensure they don't punch you in the face. Use a gentle high-cut filter (around 5 kHz) to curb sibilance in cymbals and sharp snare hits, and apply a light compression ratio (around 3-4:1) to control sudden peaks. This way, sound effects that need a boost won't overpower your guests.

Lastly, use the "subtractive" approach to mixing when dealing with a plethora of sound effects. Instead of adding more, try subtracting the parts that clash or compete with the spoken narrative. Pay attention to spatial cues, too – a well-placed sound effect can sell an environment without screaming "look at me."