H4: Haven Tactics

Haven is one of the most popular 4v4 Slayer Maps because the layout is straightforward and easy to learn.  Even though it feels roughly symmetric, red base ("Closed Ramp") has proven to have a very distinct tactical advantage in the first week of play.

Most teams thus far are not coordinated enough to hold a position yet, so Blue can take over Red Base ("Closed Ramp") pretty easily by just walking around the outside perimeter ("Blue Street" or "Red Street").  Red Base ("Closed Ramp") is by far the best location to hold as an individual, 2-person fire team or 4-person squad.  If you are Blue and are unable to take Red Base ("Closed Ramp"), the next best options are either side base ("Blue Ramp" or "Red Ramp"), which are pretty defensible as well. From Red Base ("Closed Ramp"), there are clear sightlines to everywhere that matters on the map.  Just as importantly, there are very easy escape routes to get out of enemy fire and recharge shields.

Green arrows: When Red spawns, you can sprint up to the small platform ("Mohawk") and scope in to put fire on any Blues that venture into the upstairs Kill Box ("Top Mid").  It's very easy to back off the platform and into cover as Red, but there's not really anywhere for Blue to go once they're in the Kill Box ("Top Mid").  The small platform is also a good location to cycle around pick up flankers on either left and right upstairs.  The curve geometry of the corridors is such that enemies will show up just on the edge of your radar before they have line of sight, giving you plenty of warning to re-sight and prepare for them.

Yellow arrows: If taking fire or dealing with targets coming from different directions, it's easy to back down the ramp.  You can pop in and out from the ramp cover to take potshots, and the grenade throws from here are easy.  There are good sightlines to both upper and lower corridors once enemies are within mid-radar range.

Orange arrows: If shields are critical from upper level battles, you can very quickly drop down underneath the ramp to be safe from gunfire and grenade splash damage.  Being on the lower ramps gives direct sight lines to put fire on the lower kill box ("Bottom Mid").  Tactically, it is always easier to move/shoot down than it is to go up, so you should spend less time down here, if possible.  Enemies coming up from these ramps are easily disposed of as they have to make two turns while shooting, and are in a tight confined space.

Kill Box: There's two ways around the map, through the Kill Box, or through the perimeter corridors.  The Kill Box is exactly what it sounds like, where you go to be killed.  Both upper and lower center areas are terrible places to be, as they are exposed to fire from literally all sides.  The lower one is especially bad, as there are dozens of places to drop down into it to ambush you.  Avoid the Kill Box center.

Battle Rifle will be the most comfortable all-around weapon for most on this map, given the effective range of engagements.  Those very comfortable with the DMR will find it more effective at targets deep inside the Kill Box, but will want an AR as secondary loadout for close quarters combat around the ramps.  Ordnance drops provide Shotgun, Scattershot, SAW, Sword and Hammer, which are all excellent secondary weapons.