5 soldiers get an all-purpose "assault" loadout - first it was assault rifles and combat armor, now it's bolter rifles and nanocomposite armor. If I'm short on good soldiers and I have someone with good close but everything else terrible, I'll give that person a shotty instead, or have them John Woo it with two plasma pistols.
1 soldier gets the rocket launcher, 1 soldier gets the MG, 1 soldier gets a sniper rifle.
Everyone gets a medikit, 2 frags, a smoke grenade and a flashbang.
I divide my people up into groups no smaller than two and no greater than four, depending on the way the map is spread out and the kind of terrain they're going to encounter between where they are and where they're going.
My first objective is to set up a "front line:" I park my assaulters literally in a line, under cover or in shadows if possible, that creates a huge killzone in front of them. Everyone saves multi-shot reaction fire. I plan the route my rocket launcher and sniper will take to get to high ground and try to keep them behind the front line, in positions where they'll be useful along the way.
Once I've established a front line, where I know for certain there are aliens on one side and not the other, I just work my way across the map, eating up territory and killing baddies until the last alien(s) are cornered in an obvious location. I swing it so that there's never fewer than two soldiers with a line of sight on every possible place an alien might come from.
Aliens are terrible shots, so I'm a huge fan of drawing them out of cover and into prolonged, long-range firefights. By an absurd twist of fate, my MG soldier is a great shot, so between him, the sniper, the rocket launcher, and a prolific use of nades, those fights always end in my favor.
Another favorite is to get the stupid aliens to prairie-dog out of one door of a building, trying to pick off one of my guys who's in partial cover, while two assaulters are creeping up to the back door, then either nade the back door or just burst in and shoot them from behind.
This tactic produces lots of injured soldiers, but few deaths.
I generally ignore areas where civilians are walking from, because I figure if there were aliens there, the civilians would be dead already.