Strategy in War2 comes in two forms: Individual and Side Strategy.

Individual Strategy

Veteran players begin each round deciding how they will advance the cause of their side. Some players will choose to focus on conventional battle and gaining land, others on performing offensive intelligence operations on the enemy, and others will develop and fire rockets or nuclear missiles. Once a player has decided on a particular objective, he will choose how to develop his territory in a way to maximize his ability to achieve that objective. Since his two fundamental resources(land and turn) are finite, he chooses what mix of laws, techs, weapons production, platoon training, and agent training best positions him to do what he set out to do.

A player that wants to be the first nuclear power needs to focus above all on researching with the maximum number of scientists. Questions he faces are whether or not he should take time out to pass laws such as "Education Bill" and "Zoning Permits" which helps him get more scientists and faster but which slows down his efforts to get into research at the earliest possible time. Does he spend turns attacking to get more land, expending turns and tying up some of his land because he needed boot camps or comm zones to train or finance his attacking force?

Or perhaps our player is more interested in firing many nukes, and doesn't particularly care about being one of the first. He might not focus at all on research and instead concentrate for the first thousand turns on producing weapons, gathering land, and getting into a position where he has so much land it's very little trouble for him to amass a number of scientists perhaps double that any player could get in his first 400 turns, and thus blaze through research and become nuke capable while sitting on a vast stockpile of weapons he produced in his first 1000 turns and that when sold will provide him the cash to produce a half dozen nuclear bombs.

Nearly everything in War2 is a trade-off, but it's not always a zero sum game. Some strategies turn out better than others in many or all situations. Knowing which strategies work in which situations and knowing which ones will never work is the hallmark of a good player. It is also vital if you want to be able to understand what an enemy player is doing when all you have is the snapshot given by an intel report.

Side Strategy

That no man is an island unto himself applies as surely to War2 as it does to reality. It does no good for every Ally or Axis player to focus on getting nukes as fast as possible if the other side simply uses their doughy, scientist filled territories as landfarms and stepping stones to an easy, early victory.

In general, there are two types of wins. Early wins and late wins. For the most part "early wins" are wins that happen before the losing side has their nuclear force decisively beaten, and late wins are when one nuclear force has crushed or even annihilated their counterparts and then turned their sights on the enemy ranking force, clearing the way for a final top 25 consolidation by their side. An extreme and recent example of an early win would be AoF 23, where there was only a single nuke fired due to an overwhelming Allied ranking force sweeping aside the Axis in the top 25. An extreme example of a late win is AoF 22, where the round went 4000 turns and saw the Axis rank force dominant for the first 3000 or more turns, until slowly but surely reduced by the Allied nuclear force which had emerged triumphant after a protracted nuclear war.