I can’t hear reverberation from the room, so “sound-proofing” the room wouldn’t change the quality of your recordings there.
Before following Koz’s suggestions (De-Essing , & De-Clicking),
filter-out all the frequencies below ~50Hz , using an equalizer,
then apply Audacity’s (soft) limiter, (with make-up gain), the result is much louder.
Adding a hint of pseudo-stereo makes it sound more 3D …