Grenades, early and often.
I ragequit a for a week or two at a time when I did my blind vanilla playthrough, but eventually got it on my 15th or so attempt. I didn't do Legendary though, **** that noise.
Maybe when this DLC is on sale, I'll give Legendary Ironman a shot.
Any of you guys play on Legendary? I tried it a few times, but literally never made it beyond the 2nd mission.