Some may say that basic small-unit tactics arose from Chinese tactician Sun Tzu, who in most probability was several people and not one, famous for the volume 'Art of War'. What Sun Tzu pointed out was that the objective was to win, and provided a multitude of case histories for how to outmaneuver a larger enemy force, or to use their strength against them. Many historians will point out battles where the smaller army wins against sheer numbers due to tactics, training, or on the spot innovative thinking. Every fixed force has vulnerabilities, and guerrilla warfare pointed out the vulnerabilities of a fixed force vs. a mobile and light force.
It seems that every few generations we are learning the same lessons over and over again about strong large forces vs. small mobile forces.
Every military operation must be directed toward a decisive, obtainable objective. In LSN, most games are based on the Wipeout scenario, and some on Capture the Flag. These are the objectives, very simple, to either wipe the enemy out, or capture some specific objective, very simple. The other good news about LSN is that you know the other force will be balanced using something referred to as Force Points, or value of each unit.
Two thousand years ago the Romans used the battle tactics of formations, keeping their attacking forces shoulder to shoulder and using their phalanx of shields and spears to deny movement of enemy forces. It's hard to attack a turtle that bristles with spears. With the area-effect weaponry that gunpowder provided, these tactics became obsolete.
How to provide maximum firepower on target without first killing your own people through friendly fire, and second, not providing an easy area-effect target for the enemy is not easy. The balance between strength through firepower and vulnerability to area-effect weapons is hard to find. See Assembling A Fire Team for quick ideas about how to keep maximum firepower on target with minimum exposure.
The limit to dispersion is the need to concentrate attack power. The reason the ancient soldiers massed together was to concentrate their offensive power. In modern warfare attacks can be concentrated while the attackers remain relatively dispersed. So units have to stay close enough to be able to coordinate and concentrate their weapons on a single target. See Element Support for more details about how to disperse and regroup.
The key is placing max firepower on target without becoming a juicy target yourself - so how do you accomplish this? By recognizing enemy movement, and being able to counter it.
What could be a stunning victory can quickly turn into a rout if your force is ambushed by a few enemy Grenadiers grenade spamming your positions. Keep your Security Elements active, as the fighter pilots say, 'always check your six' and be prepared to make quick decisions based on what you see the enemy doing around you.
Keep probing the enemy positions to gain information. Always make it as difficult as possible for the enemy to get any information on your activities. If you know what he's going to do in the next ten seconds of game time, or more likely, he's forced into doing something in the next ten seconds by your application of tactics, then take advantage of what he will do.
An example: SCARS hand to hand combat system taught to SEALs during the late 1980s and 1990s was based on autonomic responses of the body, it allowed taking advantage of what the body movement would do after being hit in certain areas. This allowed a super-quick response once a primary strike was achieved, creating a cascade or domino effect for the victim. The people who learned this combat system were unanimous in detailing how many choices they 'saw' when given any scenario due to their training.
See Basic Ambushing 101 for what you can do with this information when it's used quickly by supporting elements.
Always know your Threat Axis so that you are able to deploy behind effective cover.
The following generalizations are principles to be taken only as guidelines.
It costs twice as much to attack as to defend. History records that the attacker, even when wildly successful, loses a lot more men than the defender. This does not apply to a static defense, or one that is thinly defended - as in WW2, the Maginot Line concept does not work well, whereas the Stalingrad concept of inner city fighting works extremely well. Know when you need to fight an effective defense in order to cause more casualties to the enemy than they are causing to you. When outnumbered, look for a quick Defense In Sector.
Attacking the enemy's flank, or rear attack, is twice as effective as attacking him in the front. This should not be confused and thought to have to be fought around the edges of your area, but that if you run into strong enemy resistance anywhere on the map, flanking him to provide less defensive advantage should be key in your mindset. When you see multiple grenadiers providing massive bombardment, it may be a good idea to wait for charging in until they move, or reload. (they only have eight rounds each).
Surprise doubles the effectiveness of any attack. Anytime you do something predictable your chances of getting wiped out are doubled. If you are running down a central road or through a hallway in a building, and the area map is known to your enemy, they will expect it. Try something new, something they won't expect and get your force to engage through the walls, or with unexpected strength. See Wallbusting for details about how to breach walls. (Breaching is currently working effectively in Israeli v. Palestinian counter-insurgency, along with US Special Forces Urban Warfare).
Defense strength is directly proportional to fortification strength. Nondestructible fortifications provide shelter from area effect weapons. The balance of the defensive strength is to know when to use the fixed, known location, and when to abandon it. They are great for setting up Safe Houses, temporary areas for wounded units to fall back to so Medics can heal them. Some maps have double-walled buildings, which mean that grenade attacks may not penetrate them immediately. Use these areas for regrouping your Fire Teams and as Safe Houses.
US Army's guide to Small Unit Tactics
Marines vs. Spawn