Most of the thread on this forum concern themselves with the question "what's the best value for my meager points". Let's talk about what you do with you units once you've chosen them.
Do somethingPassively sitting on your ass will lose you the game. There's something very scary about Wargame: it hypnotizes people and makes them not do anything because they're not sure they aren't making a mistake. If you make a mistake, you might lose. If you do nothing, you will lose.
If you have no ideas, send out a recon or two and try to see where the enemy is. Drop a few rounds of artillery on likely enemy positions. Send a small flanking force to enemy reinforcement routes. Mass up units and charge them in a frontal attack. Anything is better than passively sitting and waiting for artillery to grind you to dust.
Spread out on defense, concentrated on offenseWhen you're holding onto something spread your units out a little. 80 men in the same forest aren't usually needed: 20 will do much of the same function, at quarter the cost and risk to yourself. One ATGM team forces the enemy to deal with it just the same as four. Two tanks a kilometer apart are vastly better than two fifty meters apart. You'll minimize your losses to artillery and other weapon systems that target ground. You'll also have a networked defense that is harder to sneak into.
When you're taking something, concentrate your forces. Hit it with artillery, put some serious firepower into the area with tanks and choppers, have infantry ready to consolidate when you drive the enemy away. Attacking with one or two tanks isn't going to cut it. You need to hit the defenders so hard they have no chance of recovering before they're overwhelmed.
Keep a reserve at handIt might be a loaded Buratino, a couple ATGM helis, some armor. Just have something at hand when things inevitably go pear-shaped and you need extra firepower. Victory goes to the deserving, and by deserving I mean the side with more guns.
Keep a few points in reserve. Those can come in very handy.
Spend a minute to think what you could do with a small reserve in attack and defense, if you never have. The possibilities are bigger than they would seem offhand. One helicopter in reserve means you have one helicopter in every part of your line as long as you only need it in one part at a time.
MoveDon't waste your men. If you can't win even with reserves, call off the attack and drive back. If you build your defenses properly, your network can absorb and wear out enemy offensive even when you move people out from one part of it. This is especially important for HQs, artillery and other prime targets. Don't feed a failure.
If you see artillery hitting you, move out. The strike can't retarget quickly enough to follow you. If you see rocket artillery mid-air targeted at your rear areas move your most expensive things around. Chances are your enemy has an idea where you are and decided to say hello. You'll lose one or two points while HQ is moving and save 200+ when it isn't destroyed.
If it can be seen, it can be killedHide your units. Here's an
educational video. You'll have to expose them during attacks, but up until that moment they should not be seen.
Do not leave tanks and other valuable front-line targets into places they can easily be seen. That's an invitation for accurate and deadly artillery fire. Especially do not leave your HQs in open areas unless you want a precise inventory of your opponents available artillery resources hitting the area 10 seconds later.
Moving supply units that are seen are not an artillery target. Still supply units are.
One more thing: look at the mini-map every now and then even when the klaxon isn't wailing, and especially when it is. It's not rare to see enemy APCs roll into your rear areas. If you can spot them in time, dealing with them is a lot easier.
Reinforcements win the gameIf you've got 3 points more income than your opponent, you can sit and wait on the defensive. Those points will build up a force large enough to destroy him over time. The safe bet is to build a good defense network, keep 50-200 points in reserve and spend everything extra towards artillery and other powerful units. Conversely, if you're down on points you can't wait forever. The longer you wait the more powerful your enemy will grow. Refer to the first point on this list for more information.
Who dares winsWhile attacking is hard and incurs a risk of losing, it also puts the pressure on your opponent. You get to choose where to attack, with what and how. Many beginning players shut completely down when they see they're under an attack they don't know how to stop. Even experienced ones need a small while to deal with your attacks in a proper way. Use this to your advantage.
If you intend to hit your enemy from behind, make a small diversion in the front. It's hard to prioritize the huge red strobes on minimap. Five extra seconds can make a huge difference, half a minute almost certainly will.
There are other things to keep in mind also, but these should get the ball rolling. Experienced players, please feel free to chime in.