You mean in battle right? Well I would say use augments that help cover your party weaknesses. A very useful augment for battles is "resist flinch XX" I would recommend you that one.

If you want augments for exploration one of my favorites is "Terrain Damage Reducer XX", It helped me in caldrous because it reduces lava (and all terrain damage) by 100%

The game's more modular than the first, so it depends on the situation and your own strategy. If I can work up the energy, [Species]-Slayer XX is quite effective, because all damage from all sources gets multiplied for each character. I stopped bothering because of the hassle of gathering the drops needed to make them/constant reequipping, but it was superhelpful when I first started tyrant hunting.

I personally use TP skills as the coup de grace, so Potential augments also find slots in my equipment: without them, I'm usually doing 1/2-1/3 the damage.

I'd say Potential Up is the most important, followed by Treasure Tracker when trying to craft endgame equipment, with TP Gain being a good backup if you can't keep the Overdrives coming in steadily enough. But there are others which are also very situationally useful, such as elemental resistances (Boze's final boss pretty much requires electric immunity) and species-specific attack augments (which can more than double your damage to that race for all attacks).

Yeah, potential and that augment that gives me 20 TP for every shot fired are the most useful so far.

You mean when he activates the shield? You have to fight against the smaller enemies when he does that.

Keep that in mind for a later battle...

I think he's referring to the on-foot portion of the battle.

Right, but that shouldn't be a problem, it gets difficult against the Skells if you have no Skell yourself. You get an opportunity to enter them before the last part.

Yeah, it's a bit creepy how upset some people are at being deprived of playing a 13 year old in sexually suggestive clothing.

In this instance, I support Nintendo's "censorship".

Kill regular enemies at first, leave female and male bosses for the end. This formula work on any Xenoblade battle with bunch of targets on the screen.

How do you make the TP augment?

Find all required materials and make it 

...I'm not an idiot. I get that. I mean what are the materials. When I try to make it, it says the materials are unknown.