Well just starting I like to have Ramza as a Knight and the rest either Knights or Black Mages. Some with Item others with Basic Skill as sub-commands.

Later on? Ninja Calculators. Make everyone get all the good spells from Oracle, Time Mage and master white and black mages. Get them to master Calculator class and then make Math Skill the second command for a Ninja. Do this with 5 units and you have a power team.

Equip them all with Chameleon robes and Go holy the hell out of your enemies first round and then run up and quickly slash what's left of them. With chameleon Robes you don't have to worry about taking damage from Holy if you calculate it on yourself as well as the enemy. 5 of those will basically kill anything.

Another fun team, but not as powerful, is the gun squad. Mustadio as Engineer, 2 chemists and 2 mediators. Mustadio snipes while the rest use blaze/glacier/blast guns to dispatch the foes from afar. As fro subcomands and equipment, that's up to you. Charge does well, as does knight breaks techs if you're fighting humans. Equip the strongest stuff, nothing special.

Aside from these, I'm pretty bland from specialized parties.