First and foremost, always have a self-revive on hand. The Rambo-Commando mentality isn't going to save you from 40+ foot-mobiles with assault rifles, Claymores, gassers, bomber-dogs, little birds, and Juggernauts. You will have to face ALL of them eventually.
First starting out, by all means do the mini challenges (headshots, rampage, killstreak, etc..). This will get you more cash to get better weapons. Do NOT buy anything that isn't necessary like RPG's, small arms, AA-12, etc... Not even body armor. Reason being, once you get up into the higher rounds, they're going to chew straight through that armor like flies on a shit.
Best weapons, perks, etc..
Perks: Sleight of Hand + Self-Revive
Primary: L86 LSW + foregrip and ACOG (MG36 with same attachments does pretty well too)
Secondary: Striker w/ foregrip (coupled with Sleight of Hand, this is an extremely deadly weapon)
Explosives: Re-up on flash grenades, frags, C4, and Claymores
Extras: Always have a GIGN team with you (riot squad), Predator missile (learn the spawn areas and you can get Quad Kills, Killstreaks, and Rampages with the same missile like no one's business), and two mini gun sentrys. I prefer the MG sentrys because the MK19 sentry (grenade launcher) has a much slower rate of fire, making it very prone to attacks. Not to mention, it's an extra $1,000.
How to easily take down Juggernauts:
IMO, Juggernauts are the easiest to kill. Easily outran and they're extremely slow. Once you get up to Wave 2X (Armored divisions vary throughout the difficulties, you'll get 3 Juggernauts in the waves 25 and up I believe), you'll be facing upwards of 3 Juggernauts, 2 carrying riot shields. There's 2 ways to take care of one or multiple 'Nauts, one is to get one to follow you, and then purposely run towards another. They will both, or all three follow you in a small group, making them sitting ducks for an AC130 airstrike when you flashbang them to get them to sit still for a minute. If you're low on cash, the next easiest thing to do is to rush him with your Striker, constantly circle him, and keep blasting at his face. He won't have the speed to steadily shoot at you, and his melee attacks will be too slow to hit you. This is only effective though when he's the only enemy left.
How to take down large groups of hostiles:
Find a spot where you can get a good bottleneck going (for those who don't know what a bottleneck is, it's an area where there's only one point of entry for bad-guys, two entries at the most. Three or more and you're pretty much screwed). Bring both of your turrets with you, you'll need all the help you can get. This is where your LMG's are going to come in handy, large magazines and a steady shot will help you here tremendously. When they all pile through that entry, let 'em have it! Your turrets, GIGN team, C4, and constant fire from your LMG's will thin them out in no time.
Other handy-dandy tips:
-When the gassers start coming in, wait for them to group up with others. Once he's taken enough damage, he'll explode, injuring or killing other hostiles.
-If you find yourself overwhelmed, RUN. Make sure that you know your map good, I've had plenty of times where I ran to the wrong places and would get surrounded, thus ending my match.
-If you like dumping half a magazine into one guy with an assault rifle, by all means go ahead and pick up the better ones the enemies drop. This will save you some money on going back and forth to the weapon armory to stock up on ammo. The ACR 6.8 and the FAD are both very accurate and very damaging rifles.
-When in doubt, spray and pray.
-Refrain from using any of your flashbangs or frags unless you really need them. (i.e surrounded by a large group, facing Juggernauts, etc.. Whatever makes for a quick escape)
-Try to find an area to post up that's close to all of your armories. A nice little place to camp out where you can reach your weapons armory, defense & explosives armory, and air support armory. That 30 seconds between rounds goes very fast when you have to pay a visit to all three.
Got anything you'd like to add or want to share your strategy?
Edit: Forgot to add why I don't put a sight on the Striker. I prefer not to put upgraded sights on the Striker simply because when you're in a jam, you need to be able to move quick. The foregrip will add a surprising amount of reach and help your accuracy when hip-firing. When you're aiming and circling a Juggernaut for example, you will be moving at about the same speed he is, and it'll be a lot easier for him to make the kill shots on you first.
Edit no. 2: Just now thought of this. Believe it or not, busting out as many windows as you can between rounds can save your life. Why, might you ask? Because if you run into a building and get jammed up, it may just shave a few seconds off of a melee to bust out a window before making your escape!
Edited by Lucky4Designs, 05 March 2012 - 01:20 PM.