Ideally, given what they are based on historically and what is in the sets:
The Bulldogs never have enough ammo and tend to rely on bayonet charges with initial covering fire more due to this, focusing on getting into CQC with their opponents.
The Grognards focus on trench and fortification tactics with a heavy emphasis on shock attacks for more offense actions.
The Raumjagear focus on mobility, with commando and paratrooper tactics.
The Einjar rely on updated shield wall tactics alongside commando style raid operations.
Cannonfodder use various tactics if they are organized; they often steal the weapons of fallen allies and enemies.
The Spiders use various tactics as there are many cultures and racial groups among them. However the two most common tactics are massive human wave tactics in large groups and in smaller groups or as individuals guerrilla/anti-guerrilla tactics with a heavy emphasis traps and ambushes, they are also very good at starship to starship defensive fighting.
Like the spiders and humanity the lizard men are varied race with several different tactics and strategies to draw from. But the two most common tactics are guerrilla tactics with a focus on stealth and night raids and in larger groups what can best be described as Napoleonic firing line tactics with assault rifles thrown in and chemical weapon cloud cover.