The economy is arguably the most important aspect of Red Alert 2; for without money you have nothing - hence a good economy is vital to win a game.
There are two basic methods of having a good economy; to build a lot of refineries, or to build a lot of harvesters. Whilst both of the aforementioned methods have their advantages and disadvantages, I favour the first method. The fact that I am a Soviet player is further reason for that: The aim of an Allied player should be to keep his forces strong enough to hold off a Soviet attack whilst trying to build a battle lab as soon as possible. The Soviet players aim is, to put it quite simply, to build as many rhino tanks as possible - hence you don't want to be building harvesters in your war factories. The opposite is true for the Allies - they don't want to be building ore refineries as it will result in taking longer for them to put up a battle lab. As Allies I would recommend building one war miner out of your war factory (but not on very small maps - just go straight for grizzlies in this instance).
Building ore refineries is a lot easier than building harvesters for the Soviets; to balance building harvesters and other units to fend off enemy attacks is a much harder task for the Allies. It takes practice to be able to balance production - yet when mastered is an extremely powerful skill. It is possible to get a battle lab up within six minutes, the "average" Soviet tank rush occurs within 5-8 minutes; so it can be hard to balance the production of your forces as well as harvesters. If you succeed in building a good economy as well as getting to high-tech quickly, your chances of winning the game, especially if against a Soviet opponent, are excellent. Obviously it is also possible to hold off or even attack with groups of grizzly tanks - they may not be as powerful as the rhino tanks, but if used well and in superior numbers, they are more than capable of destroying them.
You should always aim to have a superior economy to your enemy. If you do, you can build more units and more structures, which should result in a win, unless you are out smarted by your enemy. Tactical awareness is something that cannot be taught. It is something gained through practice and experience; the only thing that I can recommend is too keep looking at what your enemy is up to, and to adjust your game plan according. Scouting is discussed in Section 4. It is vital as you have to be able to see the most important parts of the map in order to see what your opponent is up to. It's also vital to uncover the shroud in his base to see exactly what he plans to do with his economy. For example, if he is building harvesters and nothing else from his war factory then you must either build the same amount of harvesters or attack him while he has a weak defense. I always go for the latter option. If you ruin an enemy's economy before he has even established his forces then he will have to attempt to re-establish his economy. This will take around 2-3 minutes, enough time for you to build up some more forces and then crush him. Tech buildings such as oil derricks also play an important part in your economy - these are discussed in Section 3.
In some games the only viable way to win is to destroy your enemy's economy. For example, if your enemy boxes himself up in his base by building lots of defensive structures (particularly annoying if the enemy is France) then you simply have to destroy his harvesters. Use rocketeers, harriers, terror drones, chrono legionnaires, mirage tanks or apocalypse tanks to do this as they are the most effective units versus harvesters. If you succeed in destroying the enemy's economy then you can just build your forces up and chip away at the enemy's base. If he has no viable economy then he will give in sooner or later.
There are a few simple things that can be done to give your economy a slight head-start on your opponents. One tip is to harvest the gems (multi-coloured ore) before you harvest the normal ore. Doing the aforementioned will gain you twice as much credits. If you are able to achieve a superior economy at the very start of the game then you will have a distinct advantage. One must consider whether or not it is worth making longer trips for gems (for example, on Mount Olympus it's worth going into the canyons outside your base).
It is without doubt possible to win games without more than 1 harvester and 1 refinery, but only if you go for the early kill (better known as "the rush") - this is discussed in Section 6.
The basic way to start an economy going is to build your first refinery as close to the ore as possible. This means that harvester journeys to and fro do not take as long. The best way to know where to place your structures is to know the outlay of a map beforehand. This will often allow you to dump your refinery right next to a patch of gems instead of ore. After building your war factory (after your first refinery is up), I suggest that you build two more before considering building other structures. You should sell any refineries which aren't needed (I.E. there is another refinery right next to it which can be used). Often there are several patches of ore around your base. Harvest one patch first but make sure you have a refinery ready to place by the next patch once you have consumed all of the ore in the first patch.
Summary: Your economy is vital - without it you are nothing. Learning how to achieve a good economy but manage to produce sufficient units to stop you from becoming vulnerable is hard - but without doubt worthwhile. Mastering economy is essential if you ever wish to be more than a run-of-the-mill player.