Alright, so what I have created for you here is a guide for Survival Spec Ops on the map Resistance. For this map I have 3 strategies that you can use, and if you want, you can switch strategies or locations in the map when you deem it necessary. So here is the key for the map markings:
This is the strategy that I originally tried using on resistance. Basically, the players camp inside the house in the center of the map (the one near the Killstreak box in the garden). You have sentry guns facing each way and a player aside one of the sentry guns. As you can see, the enemies completely surround you, and therefore it is an effective method to end rounds quickly. However, this strategy is ineffective after round 30 due to the heavily armored troops and abundance of jugs. The best part about this location is that it constantly provides helicopter cover, yet, can trap you inside with no escape.
This is a strategy similar to the one above, in that it involves the fortification of an enclosed area. Instead of the house, this one is in the library at the back of the map. So there will be turrets facing at the two entrances, and the players can decide which way to face. The advantage of this location is that it makes it harder for the enemies to get in, and also, there is better places to take cover inside the building. Lastly, the red circle on the map shows an escape route free of enemies, which the previous strategy lacks. The downside of this strategy is that the room is fairly small, and if troops reach inside, it can be annoying.
This last strategy is very different from the previous two in that it has its location set outdoors. It is situated on the elevated balcony next to the ammo crate. There are many advantages to this, in that it's close to the bomb crate and it's extremely close to the weapons crate. Also, there is a guaranteed escape because you can jump off the balcony railing at any point in time. It requires the two people facing the opposite sides, and crouching or staying in prone while constantly shooting enemies. The only disadvantage is that you don't get cover from air strikes like helicopters. However, with a powerful assault rifle or LMG, it is easy to take out the helicopter at the beginning of the round.