Early Grunt Invasion
Find the enemy's island with an Oil Tanker then invade them with about 6 level 2 or 3 Footmen. This often destroys the enemy or hurts them severely. Sometimes the enemy is well defended enough to fight the invasion off. There is also an ultra version of this plan where 2 Transports show up with 12 Footmen or Footmen, and some Peasants.

[ Click to Enlarge - 84 KB ] An early Footman rush catches the enemy without Grunts and a non operational tower. Had the Tower been operational it might have repulsed this attack.	[ Click to Enlarge - 53 KB ] It's not a good idea to group units for your rush on the shore as the Human player is about to discover. A Destroyer is also on hand to get the Transport before it can deliver the rush.

Offensive Tower
Send over 5 Footmen and 1 Peasant, or some variation of Footmen and Peasants. Towers are set up to their way into the enemy town or Towers are built right in their town depending on what sort of defense they have. If the enemy tries to offensive Tower you, do whatever it takes to kill the enemy Peasants building the Towers. Run past the enemy Footmen or Grunts to do so because it's the Towers that will be the most damaging, not the Grunts or Footmen.

Read more about Offensive Towers.

Island Grabbers
These people start grabbing up all the islands they can. This is usually easy to beat if you recognize it early because they are so spread out, you can head from one island to an other claiming it back just like as seen in the game Risk™. If the enemy is allowed to expand to and secure many islands, you may be in big trouble.

All Sea, No Land
The idea here is to not build any defenses, not even Towers, or Barracks, and build nothing but Battleships using 2-3 Shipyards. This is really risky and not recommended. You will have lots of ships but if someone invades you, you are dead. If you get luck or can prevent them from invading you, it works great.

Mostly Land And a Little Sea
Build only 1 Oil Tanker and use it to find the enemy. Don't build an Oil Rig. You have enough Oil, even on low resources, to build one Transport. The second you have enough Footmen, you invade. This is really risky. If your invasion fails, you are in trouble. Without a Navy the enemy will be able to blast you off the sea. If you continue to invade they will be expecting the invasion and will probably be able to more easily counter it.

Land and Sea
Build troops on your island to invade or defend AND you build Battleships and Destroyers to attack. This plan is often the best plan as it can counter nearly any other strategy. If the enemy goes all ships, invade them. If they go all land, your ships should take care of them. With this plan you are able to adjust your strategy either way.

Submarines Then Mages and Knights
The idea of this plan is to bypass the Battleships then build straight for Submarines. Build a Shipyard, get some Oil Tankers mining then using Oil Tankers locate the enemy. Build straight up to Keep or Stronghold and then build Submarines. You don't need to make a Foundry first to make Submarines and skipping it gives you a jump on resources. Many people have optimized this plan and building order such that they are making Submarines when other players are on their second or third Battleship. While the enemy is trying to fight the Submarines either stay at Keep and invade them with Knights, or upgrade to Castle for Mages. By the time the enemy has built Flying Machines to fight the Submarines, you either are invading them with Knights or you have Blizzard to kill the Battleships. This strategy when done by a master is hard to beat but is best countered by the Land and Sea plan. Use Destroyers to keep the enemy on their islands and head up to Blizzard yourself using hit and run tactics with Mages.

All Out Camping
In this plan the player just gives up all offense and plans for a defense against all invasions. The player puts a ring of Flying Machines around the island and puts Mages with Blizzard around to cast a Blizzard on any invasion. This defense can be hard to beat with Orcs. Human players can simply use Invisibility for hit and run Blizzard and Polymorph attacks. Make a Transport Invisible, then unload Mages, Polymorph the enemy Mages then get back in the Transport and run. Orc players should try to use Death Knights in hit and run attacks but the enemy can use Exorcism to finish them as they land. Try Bloodlusting the Ogres on a nearby island, put the Ogres in the Transport then quickly head over and unload ASAP.

High Seas Combat: No Ships
High Seas Combat is a special water map because you can win the game without really using ships. Players can use Goblin Sappers to blast through the Rocks to get to nearby Mines. You can also do a Foundry Hop in the streams connecting islands to hop your Peasant over to the other side. A common plan used by the experts on this map is to build an Oil Rig and Tankers. Next mine as much Oil as possible before the enemy destroys the Oil Rig which you allow to happen. Then head straight up to Ogres, Death Knights and Bloodlust. Build a Shipyard and Foundry deep in the stream away from any attack from the main body of water and build Transports. Load the Transports with Ogres with Bloodlust and Death Knights then invade. If the enemy has gone all sea or a mix, the often cannot fight off the group of Ogres and Death Knights. If the enemy has a blockade going outside your island use Death and Decay to clear it.