The first and best suggestion that I have is too be organized. Climb into your tree stand and get comfortable! Take out from your quiver three arrows -- putting two of them in "Quick Shot" arrow holders. (Quick Shot holders are a nifty little items that will screw into a tree and hold one arrow a piece.) Nock the last arrow in the bow and then place the bow into a bow holder that is mounted to the foot rest on the tree stand. Now everything is out of the way and you can move around free from your bow and arrows. This is really good when your butt gets tired.

If you're like me, you like to hold your bow in your lap most of the time. Add a sight-window pad by using any thin felt or fleece with an adhesive back. Add the same type of material to the bottom of the sight pin guard. Now when the arrow falls off the arrow rest, no more "clank-clank" sounds that echoes through the woods.  

Use plastic arrow vanes instead of feathers. Better yet, use Sims Stealth Fletch. If you have ever stood behind a wall corner while your buddy shot an arrow past you, then you know what I'm talking about.

Use a very light oil on the bow wheels or cams regularly along with the moving parts of the arrow rest.

Break your bow down and apply white grease (lithium) to the limb bolts and all adjacent parts. If these parts are dry and have a little rust build-up, you will hear a small popping sound during the draw cycle.

If you use a prong style arrow rest, add some heat shrink tubing or GAG super slick tubing. Heat shrink tubing is thinner, but the super slick tubing will last longer. The best silencers that I have found are called "Rest Implants," made by AMG. Good luck finding them. 

Put powder on the cable guard. Wipe off any oil, grease, wax, ... or whatever, and then wash the cable guard with soap and water. Sprinkle a little scent-free powder on the cable guard and rub gently with a clean cloth. Be sure to clean the cable slide from any wax build-up as well. You also can replace the existing cable guard with a GAG anodized cable guard which is a lot slicker than most stock cable guards.

Use a 100% Teflon cable slide (solid white) or a Saunders Roller Slide.  

Wax the bow string and cable regularly. Rub the wax in with your fingers. 

Use a quality stabilizer, not just a stabilizer that adds dead weight. Try a hydraulic, gel or rubber compound filled stabilizer.  Sims, Doinker or QuietTune are all good choices. 

Add string silencers.  TRU accelerator balls, puffs, fleece, GAG Rattlers, cat whiskers or Sims product. One little trick to try with the puffs, fleece, and cat whiskers is to put the bow in a press and split the bow string in half at the point where you want to add the silencer. Place the selected silencer through the split string and then tie it off. Try it, works better than just installing around the string. This method also helps eliminate the silencer from sliding down the string. 

Add a cable slide stopper to the cable guard. GAG makes a cable slide dampening system called "Super Stop." It's a rubber tube that you slide onto the cable guard. Trim the tube at the point where the cable slide comes to rest while the bow is in idle/relaxed. There are many cable guard stops on the market these days. If you want to save a little money, check at your local hardware store for a homemade rubber stop. Can't give you the name of an item, but you can find items with holes through the center that will fit a cable guard perfectly.

Make sure that all nuts, bolts and screws are tight. Now, don't go digging into the old tool box and start tightening everything down as tight as they will go. There are torque limits! A good thing to do is to add a little clear fingernail polish to the edge of nuts, bolts and screws. This will keep them from vibrating loose over time but also will allow you to easily remove them. There is a product called "Vibra Stop" that is made just for this purpose. Don't forget to do the broadhead threads!

Add some limb dampeners. Limb Savers help dampen vibration considerably, even if your bow is tuned correctly. Limb Savers work on solid and quad (split) limb bows. ShockFin dampeners also work pretty well. 

And most importantly, a well tuned bow. With all of the silencing suggestions that I have made, if your bow isn't tuned properly, you are wasting your time. Get your bow paper tuned, shooting the correct size arrows, and then apply some of the suggestions that I have given. 

Many people, including myself, like a good, fast bow, but if the bow makes a loud "thong" sound, the privilege of a second shot will probably never come if the first shot was a miss. Second shots are rare no matter how quiet the bow is, I will admit, but the chances are greater with a quiet bow. Think about it, wouldn't a second shot at the potential world record deer be nice? I would choose a quiet 240 fps bow over a loud bow that shot 8-billion fps any day.