Played it lastnight and I got a lot of soldiers killed...especially my snipers for some reason. The ant farm wasn't explained fully. I managed to run out of some resources and I didn't know where I got them from so I was far too gungho with using them. It might say in the manual but I haven't looked at it yet. Anyway after that and my horrible soldier death toll I decided to just roll through to see what happens when lose complete support from the shadowy council. Sorry about that humanity.
In tactical battles it's prudent to move from cover to cover and not overextend. I found that the best approach would be to have a sniper on overwatch, 1-2 assault guys, 1 Heavy (love the rocket launcher) and whatever else is needed.
Move carefully and after a while when the Mutons appear be very careful as these suckers like to throw grenades when your guys are bunched up.
I think the game has a very good balance.. so far i haven't found any big exploits one can use.. everything has advantages and drawbacks so you have to choose carefully and inevitably you will end up a tone point wishing you'd have chosen differently but then you adapt and make the best of it.
Pretty good game design if you ask me.