Oh wow, March of the Black Queen! One of my favorite games of all time. I even own one of those very rare SNES cartridges from back in the day some 15 years ago.
Everything about this game is so much fun, and I've played the game to death. I did the standard runthrough, the "best ending" game, the evil game with all the demonic characters, a "no flying units" game which poses some interesting problems (especially in the sky worlds), and my "girl power" variant where every unit in the army had to be female, including the leader. It's pretty tough getting started when you can only use about 30% of the starting army, and you have to use Amazons in the front row! Heh.
I also own Person of Lordly Calibre and Knight of Lodis, but honestly I don't like either game very much. Ogre Battle 64 has way too much focus on micro management; equipping and outfitting all of those units was a pain in the rear. Worse yet, the units move like slugs as they slowly creep around the map - and the maps are also tiny compared to the ones in March of the Black Queen. Yeah, the units are all rendered in early 3D, but it comes with major drawbacks. Give me the 2D icons from the SNES game any day; I always would play on maxed speed, and they fly around the map. But the death knell for Ogre Battle 64 is that you can't control your units as fully as in March of the Black Queen. In the SNES game, I would play my Wizards like a fine instrument, swapping between "Best", "Strong" and "Weak" a half-dozen times or more in each battle to isolate individual enemy units and slay them. Played with skill, you can destroy enemy units completely and almost never send them running back to the base. But in Ogre Battle 64, the units just kind of did things on their own, and that killed my enjoyment completely.
The tactical map makes Knight of Lodis a fundamentally different game. It's not bad, but it's not the same game either. The real killer in that game is that the AI is a complete moron... like epically stupid about moving and attacking. While March of the Black Queen's AI is simple, it's also effective.
Anyway, I could go on. If you want a quick intermediate/advanced tip, try sticking one Hawk Man/Eagle Man in each of your units. Even though these guys have pretty poor stats, they will turn the unit into Low Sky and grant the others great movement. You can make all or nearly all of your units Low Sky that way, and it makes the game very easy (maybe too easy...)
Semi-exploitative tactics include keeping all of your best weapons unequipped and then equipping them right before your units go into battle; you can use Brunhild in every single fight that way. Yes, it's very cheezy. You can also take much of the challenge out of the game by abusing the "Boots" (Seven League Boots) items, which allow you to warp units around the map. Send a High Sky unit ahead to capture a town, then warp in the rest of your army. Or make certain you never have a city recaptured by warping in defenders. But honestly, the game is more fun if you refrain from that stuff.
Finally, the mark of real skill in this game is never needing to use Tarot cards to win battles. I haven't posted on this website in months, but I had to address this thread!
End of 2008 totals: Wii 42m, 360 24m, PS3 18.5m (made Jan. 4, 2008)