Kino Der Toten -- Map-Specific Strategies
Every five or so rounds you'll hear different music signaling the coming of hellhounds, which some might remember from "World at War." These pooches won't ever appear WITH zombies; they get their own round. Your best bet for taking on the dog is to pull out a shotgun, form a battle line (preferably behind a bunch of claymores, if you've purchased them) and go for headshots.
Dog rounds can be intense, but there's a bright, shining light at the end of the tunnel: the last pooch to die always drops a Max Ammo bonus. Make sure everyone reloads before you grab it, to better maximize the ammo gains.
Upgrade Your Weapons
Both maps feature a Pack-A-Punch machine, where 5000 points can be spent upgrading one of your weapons (you get an ammo refill for the weapon as well, FYI). Getting there in Kino Der Toten isn't too tough, it just takes some planning. Starting with the set of double doors on the second floor of the room you start in, work your way through a series of rooms (and doors) until you get to the theater.
Flipping the power switch -- located right near the purchasable M16 -- raises the curtain. Jump off the stage and head to the other end of the room, paying to unlock one last set of doors which open back into the starting room. With the power now on, flip the activator switch in that starting room and then head back to the theater stage, where the impossible-to-miss teleporter will now be active. Hop in and you're whisked away to the Pack-A-Punch machine, a completely zombie-free room overlooking the theater. You only have 30 seconds to spend there though, so do your business at the machine as quickly as you can.
Back Alley Bliss
The best place to hole up on Kino is a small alleyway located just a few rooms past the theater. Right near the power switch/M16 (claymores are on the wall opposite the M16, FYI) is another door. Open that and follow the series of rooms until you reach a set of stairs going down to an alleyway. There's a fence you can open here BUT DO NOT OPEN IT! As long as that fence is closed, you can only be attacked from two places: the stairs you came down to get here and a ground floor window off to the right of the stairs. Skillful players won't even bother with a crawler; from here, you can easily keep a single zombie at bay at the window, rebuilding a plank at a time as it tries to break through.