[Eagle of Fire]

My own default team consist of 10 soldiers and 1 tank. The tank is basicaly the fodder. I use it mainly to scout, and it will seldomly fire at Aliens to kill them (I let my soldiers do that: I want them to improve their stats, what the tanks can't do). They are well armored (and the first basic AP tank is your most armored unit until you field power suits), thus able to get a few hits before going Kaput, and serve their first function very well: die and take shots instead of my real strenght, the squaddies themselves.

Plus, they are very usefull against bigger units like Reapers and Cyberdisk as their AP ammo is powerfull enough to soften them enough for the squaddies to get the kill with riffles.

I always designate 4 squaddies as "UFO Busters". Those squaddies have the best TU and Reaction combo of all my soldiers (accuracy is not that important in closed spaces) and their main purpose is to get inside the ufo and clean it out. They do help en route, but the other 6 squaddies are there to mop the rest of the map.

This combinaison usualy make a great, specialised result.

Edit: Ah yes... But you probably already know: Never leave the base without as many flares in your SkyRanger than you have squaddies. Look where your craft land, and if it's dark or night time then give one flare in the second hand of all your squadies. And don't forget to throw them to see the Aliens! Sectoids in particular see way better than your soldiers in night time. You need those flares to fight back and cut the advantage to your side...