Years ago I remember reading a response posted to rec.aviation.military in answer to a user asking how he could make his military flight simulator more realistic. He wanted to build a realistic cockpit setup for his “misions.” This is the response to the best of my memory:
Take two cynderblocks and place them together on the floor in front of your PC and monitor. Find a piece of plywood and place it behind the cynderblocks and prop it against something sturdy like a wall. Arrange the cynderblocks and plywood into a seat. Stretch a thin piece of fabric over the cynderblocks. This is your ejection seat.
Obtain either a heat lamp or an old doctor’s examining lamp. Place it next to your ejector seat so that the lamp will be shining directly on your head. This will simulate the sun. Angle it toward your eyes for ultra-realism.
Take a backpack and fill it with old cloths, rope, and tools. Pack it as tightly as possible. Try to compress it so that it is as flat as possible. Make sure something sharp is located right between the shoulder straps so that it presses into your back when worn. Strap it to you as tightly as possible. This will simulate your parachute.
Make a bologna sandwich and leave it out for a few hours. Then gently wrap it in plastic and step on it. Toss it in a small box with a badly bruised apple and a warm box juice drink. Close the box. Step on the box. Place the box under the heat lamp in your “cockpit.” This will simulate your box lunch for your mission.
For ultra-realism find a real military style helmet with oxygen mask. Strap it on tightly. Soak a rag in kerosene and let it dry. Then place it in the tube connected to your oxygen mask. This will simulate the on board oxygen system of your aircraft.
Now you are ready. Turn on your heat lamp. When the ejection seat feels warm go ahead and have a seat. Turn on your PC and get your flight simulator software going. Once your aircraft is loaded on your computer and ready go, sit there for an hour. Go through the checklist while you are waiting. After an hour under the heat lamp, begin your mission. Make sure it takes at least 4 hours. Do not under any circumstances leave your ejection seat during this time, that’s cheating. Feel free to enjoy your lunch at any time.
For even more realism, have your wife wake you up in the middle of the night. Put on your flight suit and helmet and run down to your simulator. Put on your helmet and parachute while you are running to your “aircraft.” Get in and fire up the PC. Go through the checklist and then sit in your cockpit waiting for your launch orders. After an hour have your wife come back and tell you to “stand down.” Shut everything down, take off your gear, and go back to bed. Have your wife do this a couple times per week and even a couple times per night at completely random intervals.
Congratulations! You now have the most realistic flight simulator possible.
At least, that’s how I remember it.
Air Prayer 
I would add the following:
Once you finally launch on a mission, at random intervals have your wife
come and place a 3×5 card over part of the display, preferably a part of
critical importance to the mission you are flying. This simulates the loss
of systems while on a mission.
Have your wife stand by with an air horn – any time you receive a
transmission in the sim, have her randomly fire off the horn, deafening you
and blocking at least part of the transmission. This simulates transmitter
or receiver failure or the inability of some idiot to keep the mike button
held down the entire time they are trying to say something.
As you enter into the target area, to simulate AAA, have your next door
neighbor randomly fire his hunting rifle through your game room window (have
him close his eyes if your ECM display is not covered by your wife’s card or
if he owes you money). Have his kid throw firecrackers through that same
window – that’s flak. If any of this actually hits you, go sit in a 4 by 6
cell for six years on a diet of half-cooked rice – this simulates being shot
down and taken prisoner.
When you attack the target, have a medium sized elephant kneel on your chest
as you pull off your bombing run. This simulates your G-load.
If doing a visual run, have your wife occasionally turn off the monitor –
this simulates localized bad weather. If doing an instrument drop, have your
wife spray your visor with a hose making visibility difficult – this
simulates computer and electronic errors.
Regardless of what the flight sim says or what you see, when you return to
base reset the mission – this simulates the intelligence people claiming
that you missed. Have a group of people who don’t fly the sim listen to your
account of your flight and then have them all laugh at you – this simulates
the intelligence people discounting whatever you try to report.
Fly the sim again with the above conditions. After the second attempt at the
mission, regardless what the sim says (including that you missed), have the
intelligence people tell you the target was hit but so was a hospital so you
can’t fly the sim for three months while there is an investigation.
Fly the sim with the mission reset for the third time and all the above
conditions in effect. As you approach the target, have someone pull the plug
on your PC. This simulates discovering that you and your airplane are now
declared obsolete. You will then spend time watching other people fly the
sim – this simulates being cast aside as no longer useful.
For the rest of your life, always look up when you hear the sound of a jet
engine or glimpse a contrail – this simulates having left a piece of your
heart in the sky and knowing that, whatever the cost, it was worth it.
Lobo(AW)
VMFA-115, VMFA-122
F4-B Phantom II RIO
316 combat missions, N & S VN, Laos, Cambodia