Harpy Hag Hoodoo
Since they are fast and strike with no retaliation, Harpy Hags can be used to attack neutral stacks which are much more powerful than they are. To make this work, you need to be facing enemy troops with a speed of 4 or less, or use the Slow or Haste spells so that your Harpy Hags are moving more than twice as fast as the enemy (or some fortuitously-placed obstacles). You can then choose to wait, to make the enemy move first, swoop in and attack, then, when they get close, hustle to a new location and repeat (beware Morale bonuses by the enemy, however!). In a multiplayer game, this can take some time to do and hence is frowned upon, but early on in a SP game you can use it to clear mines/guardians you would otherwise not be able to, at least until your Dragons become available. This tactic can basically be done with any non-retaliatory creature (Cerberi, Arch Devils, Sprites, Vampire Lords), but the HH's are the only one to return to their original hex.
Cooking the Books with the Treasury
The Treasury can be extremely useful during long games on larger maps. If you let your gold accumulate week to week, buying only essential troops and buildings, in a month or so your gold stockpile can mushroom to humongous levels (1 million gold or more). The interest rate is equal to Treasuries Owned x 10%, so if you have 4 Rampart towns with Treasuries, that's 40% per week. If you start with say 100,000 gold, with a daily income of 10,000, you will, after 4 weeks, indeed have over 1 million gold. But the downside is that a Plague will kill off half of all unpurchased troops in your towns, so I'd start saving AFTER a Plague (as I've never seen two Plagues happen within 2-4 months of each other). (On the contrary: I've seen a plague at the end of both Month 1 and Month 2, but it's very rare. --Memetics)
Wraith Bomb
Wraiths can be useful after all! Send out waves of expendable heroes against a dangerous invader, each with 7 1-Wraith stacks, with the aim of reducing his spell points. You will need lots of extra gold of course to make this work. This, of course, works better against the AI than it does vs. another human and is countered by Destroy Undead, but if you have the Pendant of Death...! And even getting your enemy to cast Destroy Undead over and over is going to cause him to lose spell points. Considered a "gamey" strategy by some...
Castle Siege
Attacker Hypnotize an enemy troop and open the drawbridge.
If the enemy has only Fort (early sieges) and you have strong shooters, block the drawbridge with your unit, preventing enemy from getting out of the castle.
Six or seven stacks of cyclops kings can reduce a castle to rubble in as little as two rounds.
Defender Block an open drawbridge with Force Field.
In a Tower town defending against an AI, send a lone gargoyle to stand on the top or bottom mine after at least one ground troop has advanced all the way to the castle wall, leaving several hexes between the gargoyle and the nearest ground troop. In many cases, the ground troop will walk through every mine on the way to kill the lone gargoyle, and sometimes die before it reaches its target.
In a Fortress town defending against an AI, when a wall is at risk for coming down or has already come down, send a lone serpent or dragon fly to stand immediately outside an intact section of castle wall, not adjacent to an enemy. The two-wide moat means that no creature will be able to attack you without getting morale. AI creatures will typically prefer to approach your dragon fly rather than try to make their way to the weakness or hole, thus ceding their turn. As soon as your fly gets another turn, move it to another location against the wall and watch the AI waste its turn walking up to you again.
When the enemy has no or relatively weak flying or ranged units, and you have the Castle built, don't ever attack with non-ranged units until he can get within the siege wall. By the time he manages to get closer, his army will be much weakened by the arrow towers and your ranged unit(s), so you can beat even much stronger enemies.
If the attacker has strong walker units, destroy the catapult as soon as possible by spells and/or ranged units. The arrow towers will do rest of the work.
In order to bait enemy to attack your castle, put your hero into the visiting section and units (no hero) into the garrison. The enemy will attack your "weak" hero outside, only to be met by siege battle.
Open-field battle
Remove Obstacle is a possibility when:
- a troop in your army is blocked in its starting position by a battlefield obstacle.
- an enemy shooter is protected by a battlefield obstacle.
Extra nasty Berserk
If you have Berserk, and are fighting at least two stacks of Dendroid Guards and/or Dendroid Soldiers, try using it to get them to attack each other. If you do, they will bind each other, making them both unable to move.
Using Master Genies
When you have Master Genies on your hero and have several creatures slots free, split your Master Genies to several stacks so you could benefit from their spell casting ability with additional casts.
No spells, or?
The Orb of Inhibition seems slightly bugged. It doesn't stop the Armor of the Damned or the Angelic Alliance from casting their spells at the start of combat. Especially in the first case, this can give you an enormous advantage.
It goes on and on
Clone helps double your manpower if you cast it on troops that number well over 500 (5 or 10 if it's concerning LV4+ troops). They also still retain their abilities, so that means you can spam Resurrection with Archangels, general blessings from Master Genies, destroy fortifications with Cyclops Kings, or even deliver the extra deathblow with Dread Knights.
Decoy
When a strong enemy approaches your castle, buy some random heroes and spread them in different directions. If placed correctly (not always an option), the enemy can't capture your castle the next day because he has no movement left. Useful when you need that extra day for troops, or when your main hero is just a few turns out of reach. You can also trigger the enemy's "bonus till next battle" this way.
The Admiral's Way
The Admiral's Hat negates the movement speed loss while boarding or disembarking a boat. For AI opponents, this is 'impossible', so you can trick them easily. Requires: The artifact, enemy castle nearby water. This trick is very useful when you have to attack a well-guarded enemy castle. Approach the castle (by boat). While enough movement remains, disembark and flag some nearby mines/dwellings. Before your turn ends, board and make sure the enemy can't attack your boat from the shore. Since AI opponents think you need an extra turn to disembark, they will re-flag their mines/dwellings. If they can't make it back to their castle, you can simply take it the next turn so you are the one defending the castle. You can also quickly refresh your troops if you happen to have Town Portal and Expert Earth Magic. You can combine this trick with Decoy (above): Instead of flagging mines/dwellings, pull him out with a decoy hero while your real hero waits at sea.
Grand Theft Boat
Related to the above, this is a hilarious tactic which involves stranding an enemy hero on a desert island. Tactics like having a secondary hero rescue the primary one are usually too advanced for the AI, so you can take a powerful army out of the game with this simple trick. There are several ways to pull it off:
1. A means of water-walking, flying or Dimension Door and either Scuttle Boat or the Admiral's Hat. If you catch an enemy disembarking on a small island, get to the island using one of the aforementioned methods, then either scuttle their boat and get away (usually only possible with Dimension Door), or grab their boat and set sail. 2. You can do this with just the Admiral's Hat: land on an island, let the enemy land to attack you, scuttle one boat and abscond with the other. 3. Same as the above, but with just Scuttle Boat: let the enemy land to attack you and scuttle both your boats, trapping the two of you. Then use Town Portal, engage the enemy then retreat/surrender, or sacrifice your hero.
This will not work if the enemy has water-walking, flying, Dimension Door, Town Portal or (possibly) Summon Boat.
Mix and match
If you like to play the diplomacy way, make sure you always have an extra hero following your main hero. Either split one stack in two or just keep one slot open. When a non-matching group joins you for free, dump them on your extra hero for the time being. When full, replace the weakest stacks if necessary. You now have an extra army at your disposal. - Weaken an enemy with a wave of accumulated creatures before attacking them with your real army. (optionally bring a third hero for this) - Adapt to the combat situation. Need more ranged creatures? Missing that fast-moving troop that grants you the first turn? Simply swap before attacking. - When you get a decent stack of pit lords, you can change all your random creatures into a big pile of demons. - Get a lot of profit from a freelancer's guild or an altar of sacrifice. - You can leave guards wherever you'd like them.