I had a couple years of severe startle response. Phone ringing, doors closing, babies crying, things dropping, people yelling, honking, anything moving in my peripheral vision, engines revving, firecrackers, footsteps where I could see them, twigs snapping, house settling unusually, etc. (These things still sometimes make me startle, but not as hard and I "come down" from it right away now). A bunch of things in combination helped me over time:
- mindfulness meditation
- singing mantra meditation (I practice out loud at home and then sing it quietly in my head during acute stress to trigger the calm mind state)
- self-hypnosis sleep audio tracks to help me to sleep/fall back to sleep
- emotional and intellectual acceptance of my response as a part of who I am
- spending the majority of my day with friends/family who accept me, startle response and all--kind people, all, for whom it is no big deal and who will make MILD accommodations to not trigger me/comfort me
- white noise machine at night set to a constant, even static noise, with the volume set fairly loud to drown out other night noises (including my breathing)
- an alarm clock that plays ocean waves that start very low and increase volume gradually (so much better than BEEP BEEP BEEP BEEP BEEP -- argh!)
- cut caffeine
- cut out some easy triggers (avoided certain places/situations whose avoidance did not deeply throw my life into disarray), just to reduce the number of triggers hitting my mind/body
As I said, after two+ years of startles that turned immediately into panic attacks that I never came all the way down from, and taking a multi-cope approach, I have whittled away at my startle response until now it is very near to "normal" levels I observe in the people around me. I am still (always was/always will be) a sensitive person, though. I now feel comfortable describing myself as a "sensitive-but-brave-anyway scaredy-poo" rather than a "haunted-and-hounded, tortured bag-of-nerves". :)