String:
NO TUBE STYLE PEEP! [X(] SIMS Leeches on String and cable/cables
Arrow:
At least keep it moderately weighted........obviously your bow will be whisper quiet with a 1000gr bowfishing arrow, but not exactly practical(Unless you happen to be bowfishing

). If you want quiet, heavier is the rule.....you' ll need to find your own personal trade off level of speed/trajectory vs. noise level.
Also, its a no brainer, but an aluminum or carbon arrow drug across a metal or other noisy launcher and then shot is another [X(]
Bow:
SIMS Limbsavers and NV limb dampeners flat out work(By themselves good,together even better)........the cable guard dampener? A little gimmicky but won' t hurt. If you want to get crazy you should see some of our " Rubber Monsters" of a few years ago! Ask Frank, we stuffed all sorts of things into, on and around our bows there for a while........style and sensibility thankfully prevailed on that one. Moleskin the arrow shelf. Make sure all cam/mod screws are tight....check e-clips.
Accessories:
LOC-Tite everything you don' t want or need to move. If you need it to move readily it shouldn' t be on a hunting bow. If it' s not tight it' s gonna make noise, so set it and hopefully forget it.
Moleskin your rest' s launchers..........flip the rest around and listen for clinks and clanks, and then get creative. If a set screw on the rest arm is hitting with a " clank" when shot ,deaden the noise with more moleskin (can you tell I like moleskin?

) Pluck the string and listen for any vibrations........if you have any buzzes, either tighten,fix or replace whatever you hear. A good vibration Dampening/noise reducing stabilizer like a Stealth,Sorbotek,Kyber,SIMS etc will help quite a bit. Vibration is what ultimately causes noise so anything that absorbs vibration is gonna help.
A good quiet release aid........ever hear how much quieter the same bow is when shot with fingers?[

]
I don' t think I' ve EVER heard a bow that was as quiet WITH a quiver as it was WITHOUT. I hate bow mounted quivers.
Bow design itself:
Some bows are just quieter than others.........pick one that' s quiet bare bow off the rack and things will (should) only get better.