To win you have to take and hold specific landmarks on the map, called victory locations. Depending on the nature of the mission, you may have to contend with just holding the ones given to you at the start of the mission. Tactics play a big part in how well you'll do in taking these victory locations. For instance, two orders, defend and ambush can be devastating and helpful if used in the right place at the right time. Also important in getting a victory is how you use command units.
Command units are a new feature to the game.
They work as a field commander, helping your troops fight better and more cohesively. But command units can only work their magic if they have other troops within their effective command radius. The radius depends on the morale of the command unit as well as the type of unit. Command units are specialized units that vary from single men to heavy tanks, and every mission requires that you have at least one commanding unit. Woe unto you as the Russians with your poorly trained large squads of men should your commanders buy the farm.