I found this posted on the interwebz by somebody named Logan Graves (an apt name), and thought that it held some water for
Shadowrun... I know that there must be more good ones out there. Anybody care to contribute to the list?

1. You are not Superman
2. Recoiless rifles aren't.
3. Suppressive fire won't.
4. If it's stupid & it works, it ain't stupid
5. Never draw fire, it irritates everyone around you.
6. When in doubt empty the magazine.
7. Never share a foxhole with someone braver then you are.
8. Your weapon was made by the lowest bidder.
9. If you can't remember, the claymore is pointed toward you.
10. All five-second grenade fuses are three seconds.
11. Try to look unimportant--they may be low on ammo.
12. If you are forward of your position, the artillery will be short.
13. The enemy diversion you are ignoring is the main attack.
14. The important things are always simple.
15. The simple things are always hard.
16. If you're short of everything except the enemy, you're in combat.
17. Incoming fire has the right of way.
18. No combat-ready unit was ever passed inspection.
19. No inspection-ready unit has ever passed combat.
20. Teamwork is essential. It gives them other people to shoot at.
21. If the enemy is in range, so are you.
22. Tracers work both ways.
23. The only thing more accurate than incoming enemy fire is incoming friendly fire.
24. Radios will fail as soon as you need fire support.
25. When both sides are convinced that they are about to lose ... they are both right.
26. All weather close support doesn't work in bad weather.
27. The bursting radius of a grenade is always one foot greater than your jumping range.
28. The only terrain that is truely controlled is the terrain upon which you are standing.
29. The law of the bayonet says the man with the bullet wins.
30. REMF's (Rear Echelon Mother Fraggers) are everywhere.
31. The best tank killer is another tank. Therefore tanks are always fighting each other ...& have no time to help the infantry.
32. Precision bombing is normally accurate to within +/- one mile (...or so).
33. Don't look conspicuous, it draws fire.
34. Cluster bombing from B-52s and C130s is very very accurate. The bombs always hit the ground.
35. Perfect plans aren't.
36. Friendly fire isn't.
37. The easy way is always mined.
38. The side with the fanciest uniforms loses.
39. Professionals are predictable--it's the amatures that are dangerous.
40. Armored vehicles are bullet magnets; a moving foxhole that attracts attention.
41. No plan survives the first few seconds of combat.
42. Expending material in combat is easier than filling out Graves Registration forms -- Ammo is cheap; your life isn't.
43. Just because you can't see the enemy; don't for a minute believe they can't see you.
44. Final Protective Fire doesn't.
45. The enemy invariably attacks on two occasions:
* When you're ready for them.
* When you're not.
46. A "sucking chest wound" is nature's way of telling you to slow down.
47. If your attack is going well, you've just walked into an ambush.
48. Anything you do can get you shot, including nothing.
49. Make it tough enough for the enemy to get in and you won't be able to get out.
50. When you have secured an area, don't forget to tell the enemy.

How very very True... All of them...

51. Even if your plan is foolproof, don't trust it to the fools.
52. If your plan "can't fail" it will.

I really like that list...

53. Anything not nailed down is mine. Anything that I can pry up is not nailed down.

This is not a Rule of COmbat... It is a Truism...

54. keep your body green and your holes clean. (you take that however you want)

55. Anything worth shooting is worth shooting twice. Ammo is cheap. Life is expensive
56. If your shooting stance is good, you're probably not moving fast enough, nor using cover correctly.
57. If you are not shooting, you should be communicating, reloading, and running.
58. Someday someone may kill you with your own weapon, but they should have to beat you to death with it because it is empty.
59. Bring a weapon. Preferably, bring at least two. Bring all of your friends who have weapons. Bring their friends who have weapons.
60. there are no rules, always cheat; always win. The only unfair fight is the one you lose.

61. It's not a suicide mission, it's a "leadership challenge".

62. If it's shiny, don't wear it into combat.

63. History is written by the winners, so you can write in all the fair play stuff you want to later.
64. If all contradictory witnesses are wiped out in a hail of gunfire, field reports you file are inherently irrefutable and fully accurate.

65. If you intend to perpetrate an attrocity and try to blame it on your enemies, make certain to use the right kind of ammunition.

66. The Best Armor is being out of range

67. The enemy can't shoot at what they can't see, but that doesn't mean the fraggers can't kill you with lucky blind fire.

68. Only hits count. The only thing worse than a miss is a slow miss.
69. Use cover or concealment as much as possible, but remember, sheetrock walls and the like stop nothing but your pulse when bullets tear through them.
70. The faster you finish the fight, the less shot you will get.

71. If you find yourself in a fair fight, you have done something wrong.

72. Only hits count. Missing faster doesn't help.

I have to say, I just about died laughing at that. It's also terribly true.

73. No battle is so pretty that you can't fight dirty.

That list has been around forever. I have a longer version of it titled "Murphy's Laws of Combat" that has a total of 115 entries that I saved to my hard drive way back in 1997. The longer version of the list can be found here.

74. There is no such thing as overkill, only "Open fire" and "Reload".
75. If violence is your last resort, you aren't resorting to it enough.
.

53b. I carry a crowbar.

76: Don't be afraid to fire through barriers. Use as much firepower as you can spare when you do.
77: Autofire is almost always better than single-shots.
78: Grenades might seem wimpy in open fields. Inside enclosed spaces, they are your best friend.
(78b: Don't be surprised when grenades remove walls and floors when used indoors.)
79: You can substitute explosives for a lockpick or b&e specialist, if you have to. However, there is no substitute for a demolitions expert.
80: The deadliest weapon on any moving vehicle is almost always the front end, placed into the enemy. Get a ram plate.
81: Always suppress the enemy if you can. This goes double when indoors.
82: Don't be afraid to retreat.
83: Always misdirect the enemy. If they are reacting to where you were, never be there. Optimally, make them think you are many places at once.