Shun the Combat Forecast.

That is, don't make it your only source of information. Know the math, check the enemies, and plan accordingly. I've noticed that people become too reliant on this feature and make too many assumptions. For instance, they won't check the stats of incoming enemies, deciding that their speedster will get a follow-up attack or that they'll find a way to do enough damage when the enemy arrives. This basically amounts to planning the equivalent of half a turn ahead at most. Maddening enemies are fast, bulky, and hit hard, which often demands some pretty precise math - especially in the early game. Just winging the battle half a turn in advance is a good way to get killed. Know your units and capabilities, know your enemies and plan how yours might kill each wave of theirs two or three turns in advance.

Taking that one step further, at the start of the map, check every unit. Identify the big problem enemies. If Dimitri has 10 AS and enough Atk to one-round your Byleth, then come up with a way to handle him before he's standing there, breathing down your neck. This may involve stealing someone else's gauntlets or getting into enough fights beforehand to acquire HP +5. If Hanneman could crit-gib Byleth and end the map right then and there, make sure you pick up HP +5 so that they can survive the triple damage from a freak crit. Alternatively, perhaps your healer with just Heal equipped can achieve the same effect.

Durability, Schmurability.

Spam those combat arts. Spam it until your weapons break. Then buy more weapons and spam them some more. No, seriously. Standard Training and Iron weapons are very cheap and combat arts provide substantial boosts to Hit, Mt and much more.

And yet, I've noticed a recurring sticking point for people I watch is that they don't use them. Part of this plays into the aforementioned failure to plan ahead, but worry about using too much durability is often cited. Byleth is a walking convoy, so even if a weapon does get fully destroyed during the course of a battle, it's generally quite trivial to swap weapons. And since weapons are also cheap, there's little reason to risk that sub-100% attack.

Why risk missing that kill secure and eating heavy, or even fatal, damage on the counterattack? Even if the unit is a mage or bow user attacking a melee enemy, whiffing that attack could mean the team doesn't have enough damage to finish off all the enemies. Just say, "yes" to Curved Shot, Tempest Lance, and its buddies.

Battalions Aren't for Damage.

At the very least, don't make that your primary reason to use Gambits. Doing so against the sheer bulk of Maddening enemies will deplete charges at an alarming rate. Which isn't to say, "Don't use offensive Gambits." They're still very strong, but their biggest asset is the immobilization effect. Got six incoming enemies and can only kill four? Maybe you sacrifice the killing power of two units in order to lock down three enemies with Gambits so they can be dealt with next turn.

And this is before getting into the non-offensive Gambits. Enemy entrenched? Stride on in and obliterate them first. Enemy entrenched and covered? Have your cavalry Stride in, take a pot shot, then retreat to safety. Don't have cavalry? Face-pull them with Impregnable Wall. Need to duel it out with 80-Atk, 50-Crit bosses with Counterattack? Blessing's got you covered. Sick of siege tomes? Retribution and Sacred Shield say, "Hi." Want extra turns for four units? Blessing of the Goddess!

Our Arrows Will Blot Out the Sothis.

Did I ever mention that Maddening enemies are bulky and hit hard? Well, they are, and facing them head on can be a daunting task. Fortunately for the player, Three Houses has a massive vault full of cheese just waiting to be tapped. And it all starts with one, innocuous little weapon: the bow.

The most basic issue that this solves is not specific to Maddening, though it is greatly exacerbated by the higher enemy bulk. The default equipment for the vast majority of physical attackers is melee oriented. Nine or ten units running around with just 4 Move and melee gear is bound to get cramped. In previous FEs, this is where Javelins and Hand Axes might come into play, but the very low Mt and very high Wt make those things about as useful as a green Remire villager. Fortunately, bows are basically lances with 2 Range, making them a great sidearm.

They also bring with them a typing advantage. One thing that will quickly become apparent is that a wide variety of Maddening enemies absolutely love Swordbreaker, Lancebreaker and Axebreaker. Even Tomebreaker has a fairly moderate representation. However, they forgot to bring Bowbreaker on anyone. At best, they've got a handful of units running around with Keen Intuition. This means that bows should almost never run into issues with reliable Hit.

On top of that, bows have a high return on investment at just about every rank. At D, a rank that even someone with a bane can easily reach, every character learns Curved Shot. While it only boasts a nominal +1 Mt, it more than makes up for that with a massive +30 Hit. This should fix most of just about anyone's Hit problems at 2 Range forever. It also comes with an optional +1 Range, which lets anyone strike from outside the vast majority of enemy counterattack ranges. However, attacking with bows beyond 2 Range does carry an escalating Hit penalty, so take care to account for that.

At D+, characters gain potential access to Archer, which, when mastered, gives the skill Hit +20. With no further conditions to the bonus, this is something that every weapon type would love to have. As a cherry on top, Gambits also benefit from the Hit boost, which lets them push beyond the +30 maximum that they would get for having more Charm (at 5 per point) than the enemy. Reliable Gambits? Yes, please.

With C rank comes guaranteed Archer certification and Close Counter - a skill that allows bows to counterattack in melee. After that, things slow down a bit, but B+ and higher grants access to Sniper. When mastered, Sniper gains Hunter's Volley, a combat art that guarantees that the user strikes twice with raised Crit and an optional +1 Range. This also puts a unit well along the road to Bow Knight, which has both Canto and an innate +2 Range.

Speaking of which, any Canto unit can fully abuse bows. Which is to say that Curved Shot together with Canto grants a unit a massive threat range. Units can approach enemy formations from complete safety and get the first strike. Or they can shoot approaching enemies and Canto out of their attack range. This gets especially silly with fliers, as maps are generally not made in any way that inhibits them. It's not uncommon for a flier to pop over a house, shred an unsuspecting ground unit, then hide behind the house again. In a similar vein, a clump of Bow Knights can use their utterly massive threat range to kill enemies without ever putting themselves in harm's way.

Have a Plan to Kill Every Last One of Them.

This may sound like a pain, but it's even worse to meander around through classes without a plan and end up with a liability. Maddening reduces EXP income of every kind, so it's important to approximate who wants to be where at what points in the game.

In general, most classes that get weaponfaire skills can be made to work in direct combat. However, there are some skills that will generally make the whole endeavour both simpler and easier.

Physical units will generally prefer Fighter for Str +2, even though Shove is the most awkward of the mobility skills. Any of the girls wanting to go through Pegasus Knight (Darting Blow) may consider picking up Spd +2 instead, but this niche assumes they're building toward getting follow-up attacks with brave weaponry. Archer (Hit +20) and Brigand (Death Blow) are two of the bigger skills that warrant building a unit's class path around. Magical units will want Mage (Fiendish Blow) and, if DLC is unlocked, Valkyrie (Uncanny Blow).

Other general advice is that Canto will typically make a unit much better. Doubly so if it's flying Canto. Also consider learning which characters acquire the personal brave attack skills like Swift Strikes and Point-Blank Volley, and route them through a class path that will allow them to easily learn those skills.

Where Did They Come From? I Was Napping.

On Maddening, 90% of reinforcements are going to be able to act as soon as they spawn. Sometimes there will be vague dialogue hints, and other times there will be odd terrain features that may indicate where they will spawn. Sometimes they'll even spawn far enough back to not be a threat for another turn. However, the sad reality of the mode is that the devs were pretty lazy and didn't rebalance the reinforcements from Hard to Maddening, likely under the assumption that the player could just Divine Pulse. There are going to be times where reinforcements appear right in the middle of your group or out of thin air. If you're experiencing a map for the first time, or can't remember where or when the reinforcements will spawn, the best you can do is try to sniff out the ones that are telegraphed to some degree.