I break my eight man group into two four man squads each armed to support the squad, and if need be the other squad. The squad functions as single body, sorta like a hive mind working together as a whole. Each squad has grenade launchers, armed with plasma grenades or ic grenades. The plasma grenades are ground clearers, while the IC grenades are are little more surgical. I call it shake and bake. Then I have two plasma blasters in each squad. They have poor range, but who needs accuracy when the gun is shoved in some orifice? Then I have one plasma rifle, which gives me a little movement and I can still go full auto. Never seen full auto fail at point blank range ever.
First I take cover always. Then each man either moves or shoots, not both. Once I'm in cover I wait for them to come to me. When they get close the grenade launcher allows me break cover shoot three rounds, and take cover again (Shake and bake). Those alien that sneak up have to find me in my cover which in most cases burns Time units. Most times they don't have time to shoot, it's like shooting fish in a barrel. The biggest problem is moving my men out the line of fire while in cover. Then I use the plasma rifles to clean up. You can move a little with a plasma rifle, full auto kills, while aimed shots finish off wounded foes. Except for large battle fields were you have chase down wandering aliens this works every time.
I never make weapons, except plasma grenades for the launcher.
With this tactic newbies work as well as harden vets. I have to keep selling alien junk or my store rooms fill up.