Editing Warhammer 40,000/8th Edition Tactics (section)

====General Advice====
*'''Cicadas and you!''': Cicadas follow an evolutionary stratagem known as "Predator satiation", other wise known as "The predators can't eat all of us!". I mention this because it's something to keep in mind. While it's true that pure armies like the archetypes listed  below take effort to use successfully, there is something to be said in running lots of something, since you know your opponent can't kill them all. It's OK to have a strong theme and have a predominance of one type of unit since you know your opponent can't wipe you out the majority of your army fast enough with the dedicated weapons they have, just don't use it mindlessly and grab nothing but Gaunts or Terminators or something. As ever balance is key, it can be an imbalance, just so long as there is some balance. This balance is mostly in the weapons you yourself can bring. Often specialising on one type of unit severely limits the types of weapons you can bring yourself (see Gaunts). If you can bring enough different Anti-infantry, Anti-tank and long and short-ranged firepower by taking one type of unit, you can make it work. This doesn't work for every unit, as for example terminators can be dealt with effectively by both anti-tank weapons and massed anti-infantry shooting. 

*'''Build an Army, not a Mob:''' Remember that your units should support each other. Generally, you want to avoid "Pure" armies, or gravitating towards one extreme of list-building. While running a pure foot horde may look aesthetically appealing, it will suffer against players running mass mechanized vehicles (plus it will be a major chore to paint, and your turns will take forever...). While running a small elite squad may play quicker (and be cheaper), each casualty *hurts*. Notable "Pure" armies that can work with some luck and effort:
**'''The Scuttling Swarm:''' Aka "Horde" Tyranids; Tyranids in theory can drown an opponent in bodies and win (This also works for Guard). Key word is "in theory." Hell, this is even more plausible with 8e letting everything wound on a 6 no matter their toughness. The issue is, most of those attacks will be single damage so will take ages to chip off points from beefy models (but on the bright side, it also makes tarpits into a potential death of a thousand cuts for even dedicated melee units/characters). Also, the aforementioned issue of your turn taking forever. On the other hand, Objective Secured has been replaced with "whoever had the most models on the objective controls it", which means a large enough horde can make an objective nigh impossible for an opponent to take. While Objective Secured is in Chapter Approved and each Codex released has added an equivalent rule to its corresponding army, that won't mean much if the swarm outnumbers the opponent's Troops, or if the opponent is relying on FOCs with few Troops slots. Also, the amount of units with the FLY special rule in some armies (looking at you T'AU) means tarpitting won't work all the time.
**'''Aspect armies:''' Eldar aspect warriors fall into this category, as do primaris marine armies. You have elite units, generally with good saves, but still weak against specific weapons. Each type of unit has its own role to play, and if your opponent takes out the two units that are a threat to him, you may suffer. Coordination and hiding your units behind terrain are key strategies to these armies as they don't always stand up to a straight shoot-out with most armies. When playing these elite armies, it is very important to be aware of what your army is weak against, and prevent your opponent from using his most effective units against you. Plus, with all of your units being so specialized, it only takes the loss of one squad to leave the rest of the force all but unable to handle a given type of opponent. 

*'''Successful tournament armies generally have a few things in common:'''
**Hard-hitting units. Things with high strength and either a large number of attacks/shots or multiple damage per wound (3, D6, or similar). Dark reapers, dreadnoughts, Manticores, death company with thunder hammers, crisis suit commanders with 4 fusion guns, etc.
**Mobility. Whilst any unit can walk around and still shoot, successful armies have a way of getting a unit where they need it fast. Options include fast units like bikes, jump pack infantry, tanks or 'deep striking' units, whether normally or with some stratagems.
**Resilience. In 8th edition, you need to be able to survive an opponents first turn with your key units intact. Either by fielding multiple key units, so your enemy can't take them out all at once, or by using transports or reserves/deep strike to keep them out of the way. Other options include penalties to hit for enemies, line of sight blockers or fortifications or characters that grant bonuses to defense.

More detailed specifics will are found in the "Individual Army Tactics" of course.

'''Small units or big units''': Utilizing multiple small units (MSU) has both advantages and disadvantages in 8th.
 
Advantages:
*Small units don't suffer as much from morale. Either the unit is dead entirely, or you will have a good chance of passing the morale test. 
*Enemies will score overkill more quickly, wasting firepower because you have no more models to remove. An enemy may score 10 wounds on a 10-man unit, or split fire and score 7 and 3 wounds on 2 five-man units, leaving you with 2 living dudes. 
*You fill detachments faster with smaller units, granting more command points. 
*Its easier to find cover or block line of sight to a small unit. 
*When shooting, it's better to shoot with 2 five-man units than 1 10-man unit, because you can see how the first five do before deciding what to shoot at with the other five, preventing overkill.
*Sergeants/leaders/etc. A unit often comes with a leader for free, with better stats. By taking multiple small units you get more leader-models for the same price.
*Small units offer more flexibility in movement and can be used as speed bumps more effectively.

Disadvantages:
*Small units are more prone to dying from overwatch
*Small units don't fire overwatch as effectively as larger units
*Big units are more resilient to being charged, as they have a good chance of surviving to strike back.
*Big units have more attacks in combat so are more likely to cause significant casualties.
*Stratagems. A lot of stratagems let a unit do something special, like shoot or attack an extra time. However, you can only use each one once a turn so these are much more effective on bigger units. If you have stratagems in mind that you think you might want to use, keep these in mind when deciding how many guys your unit will include.
*Scoring is done by counting the 'most models within 3" of the objective", so more models give you a better chance of capturing an objective, but not all models need to be a single unit. 
*The player with fewer(!) individual units will have a good chance of getting the first turn. 

With the new Chapter Approved released, each unit in the 'Troops-Slot' gains an objective secured special rule, allowing to take an objective even if the enemy has more models in range of the objective marker, as long as those models are not Troops themselves. This makes MSU built of Troops even more playable.