I have found that the beginning of the game can be crucial to resource management.
The acquisition of 'stuff' is really important. The means of acquisition are:
resource zone control and infrastructure:
you control this. Build up as soon as possible, as early as possible, because of the cumulative effect.
You might find that the placement of a resource zone is vitally important for several reasons. I think
having zones that border water offer a 'boost' because of level 3 port facilities giving a 30% bonus to
production. This comes with an inherent risk of seaborne invasion, but that is another topic.
Buy it on the Open Market,
you may see a lot of early trading going on. Resources are seldom cheaper than in the first few days.
Trade with Allies!
Some buy up all the food they can, others concentrate on Rares, so they can build facilities on
undeveloped areas to get a rapid and early boost to production. The one thing you really do not need on
the first day is $100K sitting in your bank.
Capture your resources:
As you conquer your friends and neighbors they will yield to you all of their hard earned resources. This will also get you the means to produce more of said resources. Pick targets wisely for maximum effect.
A Capitol can be a goldmine of badly needed resources, this is why many attack the AI smaller countries
early on, to get the goods and means of production.
These actions are all within the fair play rules allowed by the game.
The following comments are going to cause some feathers to be ruffled, so be it. This is not idle conjecture but has been observed in play.
There are some unscrupulous players who have multiple accounts
allowing them to have more than one country in the same round, obviously
a HUGE advantage. I know some folks use one account for Role Playing, and another for regular play. I have no issue with this double account type.
And some groups (2 or more players due to prior arrangement) trade off being the 'lackey' and join a game just to be a supplier of resources
to another player, and in kind they switch places in another round. I am not saying that those you see are using this suspect behavior, but
it does happen. 