Create an elf hero with self-heal. You can get no recharge time on it. When you want to click on it, do so but immediately move to another location. It will not recharge. You can do this as many times as desired.
Use the following trick to give a hero any power(s) desired, but it requires some time and a lot of patience. First, make a hero with no powers and then a second hero with the power desired (for example, an elf hero with Healing). Then, stack them together on the playfield. Click on the hero with the single power, then go to the "Powers" menu. When you click "Customize", immediately press the quick switch key to your hero with no powers. When you enter the powers menu, the "hero" using the powers from the power menu will be the hero with no powers. Next, click on the blank unit portrait (the picture of power will not be there) where the desired power is located and re-select it. You can now make other heroes with the desired powers you want and put them on your new glitched hero. Note: You cannot "pull" multiple powers from the valid hero unit; you will still need to add them one by one to the glitched unit.
All maps in Skirmish and Multiplayer mode have Gollum cloaked on it. When you find Gollum, kill him and you will get the ring. Take it back to your fortress and have the troop that is carrying the ring enter the fortress in order to recruit a Ring Hero for 9,000 resources. The Ring Hero does not use any command points. Men, Elves, and Dwarves can recruit Galadriel. Mordor, Isengard, and Goblins can recruit Sauron. The easiest way to get the ring is to let an enemy find Gollum then kill them after they obtain the ring. The only way to stop them before they reach their base is to chase them down with a mounted unit, have a created hero teleport into their path, or to summon allies into their path using a power.
Kill a Troll while it is still coming out of the Troll Cage and it will become invincible. It will freeze where it is, and you will still be able to shoot at it. You can still gain power points from shooting it. Eventually, it will unfreeze and attack any enemies.
First, play the Dol Guldur level a few times in Skirmish mode to get a feel of it and memorize the locations. When you start the level in the Good campaign, you must have the Tom Bombadil power and Elrond's Farsight power. Use Elrond's power and eyeball the Dark Shroud to find the middle section of Dol Guldur (the part with the fortress in it). Note: You can see the texture of the terrain as you move the Farsight power's pointer. Once you have successfully revealed the fortress area, summon Tom Bombadil just in front of the fortress. Once he is in, the shroud should disappear permanently with no fog of war. You can see exactly what the enemy is doing at the moment. You can use Bombard, Flood, Earthquake, or Sunlight, to attack enemy units and buildings, and when they are weakened, launch the assault with your army.
Do not just rush your opponent's territory. Either send in a camo capable unit or a very cheap, weak unit such as Orc Warriers. Check out your opponent's base before attacking with stronger units. When attacking, use melee soldiers to attack buildings and use Bowmen and Cavalry on enemy units.
When building a wall around your base in Skirmish mode, never put in gates; always put in Postern Gates. A Postern Gate is a small door in a wall that allows allies to pass through, but not enemies. It is invisible to the enemy, making passing through a wall virtually undetectable, and allies can pass through a Postern Gates as fast as they would pass through a regular gate.
Have a lot of defensive structures in your base and teleport the opponents to your base. The towers should kill the enemies before they can do much damage. The Convert spell will also work, because they are free men.
Use the following trick to kill armies (including brutal) easily. This strategy works best with the elves. First, get as many Mirkwoods as possible. Have them guard your fortress and make sure they get Silverthorn Arrows. Then, get Glorfindel and Arwen and three to five groups of horses. Upgrade them fully, then send them around the back of the enemy base and have them attack. This will work almost every time. Make sure that Glorfindel and Arwen are on their horses. It also helps to have Rally Call and Heal.
Start at the bottom-most part. Build as many resource collectors as possible. Then, capture the Shipright. Get Builders to build Wall Hubs where the Cave Trolls lair is found (kill it first). Build a wall, then build units and an upgrade structure. Get your units upgraded as much as possible. Put some by the wall to defend it. Send the rest to the Shipright. Build the number of transports needed. Put the units by the Shipright onto the transports. Send the transports to the enemy camp. Optionally, split your units up and surround the camp. Destroy all the structures except for the fortress. Finally, destroy the fortress.
The third level of the Evil campaign is a mission where you must capture the Shire. This mission is quite easy up to a certain point. Play the mission until you must build a base in the Eastfarthing. Build a base with two of each building (including Fortresses). Also, build at least ten Sentry Towers. Upgrade your Fortress to the maximum and build all your Fortress expansions as Mountain Giants. Stay in your base and repel all Dunedain attacks until you have killed them all. You will be notified when all Dunedain have died. Once you reach the part where you must destroy the three remaining Seats of Power, only send one Goblin horde to destroy them, as there is no resistance with the Dunedain defeated. Do not destroy the Seat of Power in the bottom-left corner of the mini-map. At this point, build a large army with at least 750 command points available. Buy all available upgrades for your Goblins. Send all your units to the large, grassy field at the bottom-left corner of the mini-map, just south of the last remaining Seat of Power. Destroy the last remaining Seat of Power with as little units as possible, then retreat a short distance to the north. You must do this because a volley of arrows will kill many goblins if you remain in that grassy field. After a few seconds, quickly return to the grassy field and a large army from Isengard will emerge, led by Grima Wormtoungue. Fight this army until only two Goblin Hordes remain in your forces. Send these troops to your base, and build as many Goblin Hordes as quickly as possible. In a very short time the army will attack your base. Do not try to defend any other buildings besides one Goblin cave and your Fortress. Uruk-Hai will destroy your forces in a short time, but your fully upgraded fortress should hold them back while you construct more Goblin Hordes. After awhile of relentless Uruk-Hai attacks, the flow of enemies should stop. At this time, re-build your base and construct a large army. Lead this army into the Isengard base and kill Grima. This part of the level is very difficult, as the Ballista will quickly destroy your units. It is recommended that you destroy the Ballista first.