These are my 10 commandments. I would gladly hear which of them you find right, and with which you disagree.
1. Expand as quickly as possible. The most important thing in the early stages. More castles means more armies, and more money, and that means… more castles, and more money, and more heroes. At early stages you can get from linear progression to the geometrical progression (don’t know if that are the right terms): 1, 2, 3, 4, 5 … vs 1, 2, 4, 8, 16 … To achieve this you have to:
2. Be active. Don’t sit in your cities. Get your armies to the frontlines. Generally you can leave just one unit (HvI) to defend your inner or rear cities (on some maps in the first few turns you can leave them unprotected – bur be careful with that). The rest of them should immediately march (early stages) or be vectored (later) to the frontlines or defend the crucial cities. If your scouts warn you about a danger (if you scout well that will be 4 or 5 turns earlier), you will manage to produce enough units to defend your cities or to attack and weaken the army heading towards you rear. For example: player A has 20 cities and 120 armies, and player B has 15 cities and 90 armies. That gives 6 units per city. But if player B will leave only one unit in his 10 inner (or rear) cities (those that away from the main warfare activities) and get the rest of them to the frontlines – he will be able to send 80 armies to fight his opponent on the frontlines – where player A will have only about 40 armies. It’s not how big your army is, it’s mainly about where it is.
3. Scout (this is what KGB taught me, due to the fact that I always played W2 were there was no FOW). Crows (Light Calvary on open maps) are your eyes and ears. They will tell you about your opponents plans (if he is coming towards you with a hero stack or just sits in his cities). The other thing is that you should never attack a large stack or a city (especially with your hero) when you don’t know what hides there. What looks like a stack of six LI or Orcs might be 4 pikemen +dragon + LI (fight order!). A nasty surprise which will cost your hero’s life.
4. Plunder. Generally (at first stages) I plunder almost every city with good production – and use the money to buy heroes with good allies. Exceptions are (a) when I already have a lot of money, (b) when the production corresponds with my tactics (i.e. elephants or unicorns on the open maps, pegasi when I have a lot of HvI in nearby cities, catapults – when I’m planning an invasion etc).
5. Buy heavy infantry. After plundering the best choice in 90% cases is HvI. It’s cheap, it relatively strong and quick, and it’s a great cannon fodder for you hero’s stacks (Hero + Dragon + 6 HvI etc). In port cities – if you plan a lot of ship battles the best choice would be pikemen or dwarves (max strength on water plus they lousy movement is insignificant on water).
6. Loot the ruins. In level three ruins you can get over 1000 gold and even around 2000XP points. Use that gold to buy another Hero.
7. Be careful with your heroes. My style of play is based on hero actions (plus taking control over the water), that’s why I never want to lose them. Never fight under 90% fights with your hero at the early stages (note that if the percentage is over 90% you will win the battle with at least 1 unit left – and that will be your hero).
8. Upgrade your hero wisely. Be patient. Wait till you have 35 points to buy command or 45 for negative stack. If you know your hero has some “safe” battles ahead of him – you can even wait to have 90 points and buy –2 negative stack (deadly weapon). Buy base strength only if your hero is in great danger (i.e. you have won an enemy city, but are left with only a hero in it).
9. Think few turns ahead. Like in chess. What’s good in 3 next turns may not be as good in 10 turn perspective. For example: if you will go with your hero to a corner of the map you will have to get back from there. If your opponents are fighting each other – it’s good to power up your self and then attack one of them form behind than to immediately join one of them etc.
10. Read statistics. Check who is the strongest one and who is the weakest. Who has lost heroes, and whose heroes has reached higher levels. It’s always better to attack the weak one (look also at their win/loss ratio!), than the strong one. Don’t engage in an early war with your neighbour if you are not sure that you can squash him. But if you see that one of your opponents is expanding too quickly convince others to join forces against him. In most cases players do that waaaaaaaay to late (when the best players has a huge advantage). I lost a lot of games because other players didn’t want to team up against the most powerful one, and won some where my opponents could have beat me easily but were fighting wach other.