Germany is the best rush faction. You have two decent basic infantry squads, so use this advantage. Always couple Infantry Squad with Assault Squad, because MG-42 is the ultimate pinning weapon of the game (it has 1200rpm fire rate). Capture one low resource point, then focus on the medium and high res control points. Keep attacking the enemy. You unlock the Sd.Kfz. 251 and Sd.Kfz. 223 with only 2 vehicle tech points, so support your rushing infantry with armored cars. Short after you should unlock the Sd.Kfz. 222 which is very good to counter enemy light tanks and armored cars. Start fortifying your position with static defenses suchs as MG-42's, mortars and PaK35 or PaK 40. The most imporant thing is the following: DON'T SPAM PANZERS. The fact German panzers are the best doesn't mean they are immortal. Be sure to have at most a couple of panzers 4 H on the map, use them to push your assault not to defend. For that purpose you have PaK 40's or SPG's such as the StuG III. Maybe the easiest support Command is the Panzergruppe because you have a decent early call in (the armored infantry which calls in a Panzer 4 H with 4 smg soldiers), an ability which allows you to replace tank losses for free and the ultimate Tigergruppe call in which is very expensive but can reverse a game. The Infantry and Luftwaffe support commands are good to cut the enemy lines, because you can use Brandeburger or Fallschirmjager to conquer a point behind enemy lines.The hardest support command is probably the Artillery Brigade, because you don't have access to many infantry units (for example you don't have elite infantry such as Panzergrenadiers and Waffen-SS) and you powerful and effective artillery barrages but you have experience to use them well.
There is not much to say about USA, maybe it is the easiest faction to play because you have decent basic infantry and you have immediately access to support weapons, such as the Browning 1919 and the M1 mortar, and jeeps. I usually start pushing the enemy with riflemen and jeeps, then fortify key points with M1919 and mortars. A good thing is to replace the M1919 with M2 because it can pierce armored cars. This is very important because USA does not have access to good early AT units except for the M3 37mm AT gun (for example they lack AT rifles while all other nations have them). Also use the M2 107mm heavy mortar to take out entrenched enemies, because it has the explosive power of a light howitzer. You can always have access to paratroopers so you can easily cut enemy supplies by dropping them behind enemy lines. You can use the P-51 bombing run to take out the enemy artillery emplacements. The easiest support command is probably the Armored Cavalry since it has a lot of call ins (3 out of 4 support operations calls in a special unit) and you have sherman mass production. The Infantry support is also pretty easy since you can spam infantry and use the Jumbo to break through the enemy lines. The hardest support is maybe the Air Force because you need to time well the bombing runs and you don't have many special units.
The UK is pretty hard because you need to use officers well. A single squad with an officer can become really devastating but you need a lot of attention and practise. Use them to break through the enemy lines quickly. I usually start rushing with infantry mixed up with support infantry and bren carriers. You have the Vickers HMG which is really good because it can pierce armored cars as defensive units (but use 2pdr as well). You have the best AT gun in the game, which is the 17pdr, use it only when the Wehrmacht starts to bring in tanks with good frontal armor such as the Tiger or the Panther. Remember that CQB squads and Commandos have incendiary grenades which are really good against infantry in buildings or even against tanks if you hit the engine. The easiest support is the Desert Rats because you have access to early tank call in and you have saboteurs which are really good to cut the enemy supplies and sabotage enemy tanks. The hardest one is maybe the Chain of Command because you have a lot of nasty abilities but no special units and you have to focus your strategy on officers which are hard to use (but quite effective).
This is a defensive faction, so if you are a defensive player you might want to start with these guys. At the beginning you have to use the fast deployment time at your advantage, so spam recon squads and capture as many points as you can. Also use the armored car which is immediately available to cover them. After you have secured a decent amount of points start digging in with infantry squads and HMG's. Remember that you have early light tanks so use them to push the enemy back but stop using them as soon as you spot the first Shermans since they are quite useless. You can keep calling in Ho-Ni tank destroyers and Type-90 AT guns. The two keys of this faction are the following:
- 200mm Naval Gun: As soon as you have 20 infantry tech points call in a heavy engineer and deploy a couple of them. They are really devastating against bunched infantry and tanks. Place them behind your frontline since they are very vulnerable to enemy fire.
- Artillery Concentration Fire: The special operation for the artillery section is really devastating providing you have at least 2 or 3 artllery units.
When you gain access to air force start pushing the enemy back. The Observed Air Strike is really good and remember you always have access to airborne replacements, which allows you to replace your fallen soldiers with airborne infantry units.
The easiest support command is maybe the Fortress Support since you have access to powerful defensive abilities such as the Observation Artillery and the 305mm Naval Bunker. The hardest one is maybe the Jungle Warfare because you have a lot of good but hard-to-use support abilities.
SOVIET UNION:The Soviet Union is the hardest faction to use at the beginning of the game. Basically the only thing you can do is spamming conscripts and try to build a human wall against advancing forces. Deploy Maxim MG's on bottlenecks but never in the open since they have a limited arc of fire. As soon as you unlock infantry modernization 1 use it to upgrade your conscripts to People Militia. People Militia squads have the flag carrier who drastically boosts your troops health so be sure to use them whenever you start attacking the enemy. After the first 10 minutes the Soviet Union becomes the most versatile faction of the game. I can't suggest you a build order since you have a lot of chances. Assault Marines are really powerful, since their leader ability allows you to shoot a devastating shot which can kill even a King Tiger. Another unit I like is the SU-122 and with modernization 2 the ISU-152, since it unlocks the artilery barrage leader ability with engineers. Also modernization 2 for infantry allows you to deploy the mortar brigade with officers which have a leader ability similar to the Japanese Concentration fire (but for free).The easiest support command to use is maybe the Tank Guard because all the support operations are special units. The T-34 Command Tank is pretty useful to replace tank losses for free. You also unlock a good heavy tank such as the IS-1 pretty fast, and you have the T-34/57 which is a good tank destroyer. The hardest one is probably the Scorched Earth support command since you have to use partisans well, but "Cut Supplies" is really nasty, especially against german heavy tanks since you have a chance to destroy their engine or tracks.But remember the GOLDEN RULE OF BATTLEFIELD: Never camp too much! This mode is focused around supply chain. If you cut the supplies you win. So you have to attack or at least harass the enemy periodically.I hope I've been helpful.