The Gentlemen and I played Horde on the new Gears of War 3 two nights ago for the first time, and believe me when I tell you, it's intense. It took us a few levels on "Normal" to get the hang of it, but after playing we quickly figured out a few key things that you'll want to do the first time you and your friends fire it up.
1. Pay attention to where you can build bases.
Figuring out where to defend against the Horde is probably the most important decision your team will make. Fortunately the game now gives you suggestions by showing places where you can build COG bases. Even if you don't spend your money immediately to buy a base (which you absolutely shouldn't), you should still use one of these areas as a fall back position when things get rough. And trust me, things will get rough.
2. Save your money and scrounge.
The first few rounds are the easiest, and although buying that sweet sniper rifle may seem like a good idea - it isn't. Try not to spend any cash in the first nine rounds and scrounge all the weapons and ammo you can off of the dead grubs. Even if you need to buy back into the game to get through round ten, it's better than wasting your money on a Gorgon pistol you could have scrounged in the first place. And later on you're going to need the money more.
3. Spot your enemies
A new feature of GoW3 is the ability to spot your enemies (a la Battlefield) so you can point out who it is you're shooting at. All you have to do is aim down your sights and press-in the left stick. Not only will you get points, but you'll be helping your teammates who probably don't have your line-of-sight. Communication is the key to any multiplayer game, and spotting only helps that.
4. Build fortifications and decoys in line of fire.
Building out fortifications at your base is an obvious thing to do, and in the later rounds it's absolutely necessary. But don't forget to build out stuff that is going to slow down the horde and give you more time to kill. On the map we played I built barriers and a decoy that were directly between the horde spawn point and the turret I built. The horde would spawn, come toward our base, and slow down just enough for me to rack up the kills. Eventually they'll break down the barriers, but slowing them down is key.
5. Keep your distance from bosses and try to ignore them until the end.
The "bosses" in the last round (of each set of ten) are difficult to bring down, and even on "Normal" mode they present a real challenge. If you've got your base set up and your game plan in place, then do your best to try to avoid and ignore them. Take out all the other horde first, because while you're distracted by that giant Brumak that Mauler inching towards you is guaranteed to take you out.
5.5 One last thing - don't forget the old lessons from GoW2 Horde.
There are a lot of cool new things in Gears of War 3 Horde, but don't forget the stuff that got you through GoW2 Horde. Play with friends and use the buddy system to revive each other if one gets taken out. Scrounge for the good weapons, plant those shields in defensive positions and get the high ground if at all possible. And, as always, Boltok-Headshot=Bragging.