Much as I love this game, I am no expert. However, I thought I’d share some of the things I have picked up to this point, hoping it helps others to overcome the learning curve and enjoy the game. In somewhat random order:
To select units from a stack, or a unit sitting on a city tile, you hold down the right mouse button and then click with your left mouse button.
The appearance of the map can be adjusted in several ways in the lower left. I like topview, but unfortunately zooming can mess that up.
The manual is very good. And even if you are not a manual reader, you will want to note the pages that list the units and their attributes. Different nations have quite different units – important to your own strategy, but also important when dealing with rivals. In general, barbarian tribes are much stronger in rough terrain but at a sharp disadvantage on plains and grass. Roman troops are the reverse. The others fall somewhere on the spectrum in between. But particular units are exceptions. The devil is definitely in these details, though. Unless you are playing at a low difficulty level, matching terrain to your troops’ abilities is really important.
Also regarding military: No more than three units per tile… you cannot even pass a unit through a tile that already contains three units! Also, a very important tactical consideration: multiple attacks on the same unit in the same turn seriously lower the ability of that unit to defend. This makes cavalry especially important because they are often used to attack first and then withdraw to safety even if they lose. Then another unit with a more powerful attack has a much better chance.
Supply is essential. Very few units can survive on tiles where you do not have 100% supply. (Settlers and sometimes your starting Nomads are the exceptions.) You extend supply by building roads and cities into areas. The other way to provide supply to a tile is to have a ship adjacent to it – a fact that makes naval supremacy increasingly important as the game goes along.
You can settle new cities with either Nomads or Settler units, but Nomads have a second use in that they are viable military unit early in the game, particularly in that they are decent in rough terrain. Settlers have a crucial second use in that they can build roads and fields and chop forests. It’s usually wiser to settle new cities with Nomads because they are cheaper to build, and it is a rare moment when you do not need Settlers to do some jobs.
The tutorial takes place on the historical map, but unless you are totally focused on the history, I’d advise getting some experience on random maps after doing the tutorial. Personally, I think that’s where the game really shines anyway… As you start out, you want to move that birth rate policy slider all the way to the right. And as soon as practical, you want to build a temple. Because in this game, population is king. You need population to do just about anything. I am not exaggerating much when I say that the overriding strategic concern throughout the game is always to do whatever is necessary to keep that birth rate slider as far to the right as possible, and to keep temples within range of as many cities as possible.
However, these two goals eat up a lot of resources. Birth rate support requires gold, stone, and wood. Temples not only have to be built with resources, but require gold upkeep. So from the start, you need to pay as much attention to the resources page as to the map – not just the stockpile number, but the accounting of yields and consumption of each, with an eye to which resources are going to be your next choke point.
Gold, stone, coal, and iron produce for you just by being within your borders, but they produce much better if connected by roads. (Building roads soaks up resources.) They then produce much better if within range of a blacksmith. (Building a blacksmith requires resources, but more importantly, the upkeep can be a serious challenge, particularly the coal.)
Thus the focus of the game is always on ways to obtain new sources of resources, while protecting and developing the ones you already have.
Military is important, but requires a lot more planning than in, say, a game of Civ. To build beyong the basic Nomad, you need a) the invention, b) the “specialization” constructed in a particular city (which better be large enough to support the loss of population), c) the production of those units, d) the training of those units, and e) the resource upkeep which can be disastrous if you are not careful. Also, two very important categories of units – ships and cavalry – are normally built in buildings outside cities, and these require their own substantial upkeep.
If you have a lot of unused military units sitting around, this is a serious drain on resources. But if you are facing a military crisis, it can be painfully slow to get sufficient units built and out to the problem area, and you may end up needing twice as many (and thus incur twice the upkeep) if you do not have time to train them. (In this sense training troops is a bargain. The costs are fairly small, one-time occurrences, while upkeep goes on forever.) Naval matters involve a more difficult calculation; naval supremacy is very expensive to obtain and maintain, but if an enemy holds naval supremacy the cost of having enough land troops to defend a broad area is also very expensive.
Diplomacy tends to be a bit of a crap shoot early on, and it is not something to get too worked up about. You start at war with everyone, and although you can make peace, the other nation will often go back to war quite soon. This reflects the fact that your rivals are in the same position you are, they do not really know yet which resources they will most lack, and which directions they will need to expand. As time goes along though, it can benefit you if you manage to establish longlasting peace with some nations. The security of such arrangements is always tentative and not the main point. Rather, once you get trade routes established, you can fill in some crucial gaps in your resources. And, even more importantly, a lengthy period of peace can lead to more extensive alliances, which can lead to your eventually absorbing another nation into your own – quite a bargain when you compare it to the cost in terms of resources and time required to add to your nation militarily. Games are often won or lost this way.
Happiness: This is listed on the resource screen, and you want to beware cities whose happiness drops, they may rebel! First line of defense is to station a military unit in or near that city. Cities added by military means are more prone to unhappiness for a while, and this is especially true if acquired by seige (starving them out). But cities can also become unhappy because you remove too much population to build units, or because they feel insecure on the border, or because some some other nation is messing with them using influence.
Influence: A sneaky way to undermine and then grab someone else’s city, especially one that is fairly small and near crucial resources. At low difficulty levels, this is your ace in the hole, you can do this, while the AI will be sparing in its use. But increase the difficulty level, and this becomes an important part of the game, and thus influence becomes a really important resource.
Oh, and one more quality of life tip… As you get later into the game, the moves of your opponents can seem interminable, but you likely need to see certain opponents’ moves. Using the spacebar skips the rest of the moves of just the current nation.