Listen to the location before recording
Before recording, listen for constant noise: ventilation, traffic, appliances, or room reflections. Turn off controllable noise sources and choose quieter positions. Record ten seconds of room ambience without speech; it can be useful when smoothing edits.
Keep the microphone close
Microphone type matters, but distance to the speaker matters just as much. A modest microphone close to the mouth may sound clearer than a high-end microphone placed far away. Check clothing noise and harsh consonants, and monitor with headphones rather than relying only on phone speakers.
Protect the recording from clipping
Set the recording level so sudden loud speech does not reach the absolute maximum. Distortion created while recording is difficult to repair afterward. If the recorder provides meters, monitor the loudest passages during a test. Leave safe headroom rather than recording extremely hot.
Reduce noise in stages
Remove obvious hums or clicks when necessary, then apply gentle noise reduction. Overprocessing can make speech metallic and erase consonant detail. Compare processed and original audio at the same playback loudness. Sometimes recording again in a better space beats a long effects chain.
Balance speech with music
When speech begins, lower music enough for effortless intelligibility. One fixed music level will not work in every scene; adjust for the arrangement and speaker. Use gentle fades at entrances and exits, and avoid abrupt jumps in loudness between shots.
Test on ordinary speakers
What sounds perfect on large monitors may become unclear on a phone. Test the final mix on earbuds, a phone, and a laptop when possible. Important sounds should remain audible at modest volume. Keep an editable project version so audio can be corrected without rebuilding the video.