Use a more efficient codec such as H.265/HEVC or AV1
Re-encode with a slower preset for better compression
Lower the bitrate only if the source has excess bitrate
Keep the original resolution if it is already appropriate
Reduce frame rate only if the source has unnecessary extra frames
Remove unused audio tracks and subtitles
Convert audio to a more efficient format and lower audio bitrate
Trim unnecessary sections from the video
Avoid multiple re-encodes
Use two-pass encoding for better bitrate allocation
Match encoding settings to the content type
Use variable bitrate instead of constant bitrate
Optimize container format, such as MP4 or MKV
Crop black bars and unused edges
Use hardware-accelerated encoding only if quality remains acceptable