Shoot and Move
One basic rule when directly engaged is to keep moving. Either keep moving towards a better firing position or away to disengage. Always move with covering fire (either supplied by you or preferrably by a buddy or support team).
Cover vs. Concealment
Cover: For our purposes, anything that'll stop a BB and prevent it from hitting you.
Concealment: Anything that prevents the enemy from seeing you.
Note the difference between the two. Good concealment is possible in a shadowy area. It's not gonna stop a BB, though. Conversely, good cover is possible behind glass...it'll stop a BB but everyone can see you. Try to go for both.
Also known as covering fire. It provides two usefull effects... it keeps their heads down and hopefully, get's 'em. By keeping their heads down, it allows your mates to move into better firing positions without them seeing where. Use wisely as it consumes ammo.
When enemy contact is highly likely, the element(s) use proper movement formations and techniques (most probably Traveling Overwatch or Bounding Overwatch). Once engaged, closest element (Lead element) provides cover and suppressing fire while trailing element quickly moves into postition to rush the enemy. The rushing element smashes through the enemy position using heavy fire while the supporting element "lifts and shifts" fire to avoid hitting the rushing element and providing suppressive fire to the enemy's flank, preventing escapes. On completion, rushing team secures the area while special teams (search, aid and litter, demo) perform duties all under cover of supporting team. Elements consolidate and continue with mission.
When elements are engaged from far ranges and the order is given to disenage, the closest element (Lead element) provides cover and suppressive fire. Trailing element falls back and prepares to give cover for lead element. Lead element pulls back behind trailing element and assumes covering role again. Sequence continues until contact from enemy is lost. Elements consolidate and continue with mission.
Elements are divided into two teams to conduct an ambush: support and rushing teams. Support team should include heavy weapons and will initiate the ambush. The rushing team include special teams (search, aid and litter, demo) to conduct duties in the ambush area. Security is posted to the flanks and rear of the ambush position to prevent the ambushers from being ambushed. On initiation, all units lay down heavy fire on enemy for a predetermined amount of time. On predetermined signal, support team lifts and shifts fire while rushing team smashes through the ambush zone. On completion, special teams perform duties, elements consolidate, and leave the area to continue the mission.
React to Ambush (Far)
In response to a far ambush, perform "Disengage from Contact" as described above. The ambushers screwed up.
React to Ambush (Near)
The main rule when caught in a near ambush is: GET OUT OF THE AMBUSH ZONE. Easier said than done. Elements outside the zone immediately provide cover and suppressing fire towards enemy position while those in ambush zone rush towards ambushers. If successful, rushing elements quickly form special teams and perform duties. Unit consolidates and drives on with mission.
Conduct a Raid
A raid is normally performed against a fixed enemy position. Divide elements into support and raiding teams, with support team containing most heavy weapons and raiding team with special teams. Security is posted to the flanks and rear of the support team to prevent from being ambushed. On initiation, support team lays down heavy fire on objective for a predetermined amount of time. On predetermined signal, support team lifts and shifts fire while rushing team smashes through the objective. On completion, special teams perform duties, elements consolidate, and continue the mission.
React to Indirect Fire
Immediately after indication of indirect fire (that whistle from an incoming round is a dead giveaway), leader calls out a direction and distance ("4 O'CLOCK, 1300 METERS!!!"). All elements run in that direction, and once there, consolidate and continue the mission.
React to Sniper
On direct fire from a sniper, all elements take immediate cover and try to identify sniper's general position. Once identified, leader can decide to engage or disengage (see "Movement to Contact" or "Disengage from Contact", above).
In response to overwhelming force or a well hidden sniper, the leader may opt to use a "mad minute". The leader calls out a general position ("TREE LINE ON THE RIGHT!") and all units blast away at the position for a whole minute (ala "Predator"), either disabling the enemy or scaring them away. Be careful as it obviously eats a lot of ammo, leaving your unit vulnerable.
Slice the Pie
When rounding a corner, stay as far from the corner as possible, slowly clearing the corner by small degrees. This allows you to clear the area of Tangoes efficiently and in relative safety.
In a non-hostage scenario, shoot the door open, and immediately throw a grenade into the room. Enter the room with short, controlled bursts to clear it.
Room Clearing (with hostage)
Force the door open and immediately throw a flash-bang into the room. Entry team immediately enter with short, controlled, well-aimed bursts to clear the room. Members should have predetermined covering positions.