It's not always necessary to fill all the empty positions with your squad members.

It's wise to often use Largo, Rosie and Alicia since they give you an extra command point.

Speaking of CPs in certain circumstances it is useful to keep some of them for your next turn.

There are often "hidden" passages that can get you faster to your objective.

Be careful while running, mines are not always clearly visible and can be very annoying.

An engineer should always stay behind your tank and use the latter to shield your troops.

Good thing I watched some of the anime or else I wouldn't know any of these names, lol.

Videogirl is right, a full team is not always a winning team especially in some missions that have multiple stages.

Also, using the tank for offensive duties is not always the best choice, sometimes a ground unit can do in one CP what the tank does in 2.

Wait, you can save INSIDE A BATTLE?!?!?!?!?!?! O_O

Yes
On the overview map press triangle (or was it start? O.o)then go to system.

If you have some team members lagging behind and you overtake an enemy camp further ahead, have the straggler retreat and then recall them (as reinforcements) at the closer camp.

Play "Skirmishes" to boost your attributes

Keep an engineer with your tank. The Edelweiss is a target. If it dies, everybody loses.

Put two team mates side by side to take out powerful foes. The second one will actually support your playable character with extra firepower if they're side by side.
Kill that enemy sniper!

Vyse is awesome. That's not a tip, though. Just an observation.

Vyse and Wendy are awesome and it looks like everyone covered the basics.

Still at chapter 8 though so I'm in the same boat more or less.

Yea I replayed the first skirmish a whole bunch of times over the past few hours before I even attempted the first actual squad 7 mission lol.

It works when you pair two members of the same class or two members from different classes but only if they like each other in the first place.

Oh and using someone who is not suited for an environement  (i.e. using someone who's allergic to pollen in a field or in a forest) will lower their accuracy and evasive skills, and will counter most of their special abilities.

Yea, I've been making sure to read their likes and dislikes. I think they need a dedicated button for stuff like that because the way it's buried in a few screens (depending on when you're trying to access it) is cumbersome when you just want to refresh your memory of a certain character.