Since we're all trying to relearn or learn the game, let's do another refresher course thing.
Let's talk about weapon types. This is fairly important as weapon types are very distinct, and knowing the difference between Radar guided and SACLOS is vital.
There's an in depth list here:
http://wargame-series.wikia.com/wiki/WeaponsATGMs:
1. MCLOS - the crappy ones. If you move your unit as the missile is moving, it will miss and do that bendy curvy thing. So basically stay still. An easy way to use this on the move is to use the attack move command.
2. SACLOS - Same as the above except better. You still can't move, but it's far more accurate and tends to fly faster too. Missiles with these also just tend to be more advanced in general and do more damage.
3. SALH / F&F - You can name the number of non-plane units with this designation in this game on two hands. They're super elite and generally you'll find them on every deck that can bring them (US and Russia basically). These guys can fire on the move with no loss in accuracy and they are usually super powerful to boot. Lots of planes have these though.
4. HEAT - Basically this means this weapon does the same damage regardless of distance. Applies to all missiles. However, you'll see them on certain tanks and vehicles and you might be wondering why. The reason is that those tanks are probably from WW2 or something like that and have really crappy damage values. The reason they have HEAT is probably some balance thing to make them at least be able to do 1 damage to their targets. This sounds stupid, but when you can buy 10 WW2 tanks for the price of one modern day tank, those 10 tanks will do 10 damage too. Still a bit worthless though, so you'll probably want to ignore these unless you have a plan.
5. KE - Default tank / autocannon designation. Nothing special here. Means they do less damage the further away they are.
6. SA - An inferior version of F&F. The only difference between this and F&F is that this requires visual contact over the enemy at all times.
7. RAD - Radar guided. Usually means it's hyper accurate and extremely long ranged. You'll find these on high end AA and certain air superiority planes. This also means they can get targeted by SEAD, which is up next. Not that it's not limited to missiles as some gun AA have this too.
8. SEAD - Anti-radar missile. Basically only works against RAD but will obliterate them. Excellent at destroying high value enemy AA unless the enemy turns off their radar weapons. It's also a good argument for not bringing too many RAD AA to begin with. This can shoot planes with RAD out of the sky too. The Soviets have a recon helicopter that has this, amusingly.
9. SMK - Smoke. Important. Make sure you have enough to saturate an area.
10. CORR - Artillery is kinda dumb without line of sight as it just ends up shooting over too large an area. This means that to maximize the use of your artillery, you need to get recon or some other kind of vision over your target. You'll know you have it with your bombardment reticule becomes small. How small the reticule is depends on your artillery.
11. NPLM - Burns stuff. Burns stuff good. Works against everything, contrary to what you might think. Kills tanks just as easily as it kills infantry. Also burns fuel, which is fun, as it can mean even if the vehicle survives it has no fuel left. Also excellent at making enemy units panic and rout.
12. CQC - Infantry that have this tend to be better at fighting other infantry on the move. Also it gives SMGs more accuracy and rifles less accuracy.
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Here's some other I think are notable:
1. Grenade launchers - Kinda the best anti-infantry weapon outside of just burning them. Some infantry units and a number of APCs and IFVs have this. Generally they're equipped as urban combat / anti-infantry roles. They stun enemies really hard. The US has a cheap helicopter that has this and it's hilarious. This can also take out light vehicles while stunning heavy ones. There is a very scary Soviet vehicle called the BMPT that also has this. It's very heavily armoured, has a grenade launcher, a cannon, and an autocannon. If you see it, don't take it lightly as it will massacre an entire town block by block if left unchecked.
2. Autocannons - Personally I think the autocannon is the king of the battlefield. Given the choice between any other weapon on a vehicle, I tend to choose the one that has an autocannon. But that's just me. I like the versatility of the weapon. Basically this gun is kinda good at fighting everything more or less (except planes). Also they kinda turn infantry and light vehicles into paste. A single Marder can obliterate an entire front of enemy light infantry along with accompanying vehicles. So think of them as heavy machineguns that can attack armoured stuff to a degree.
3. Snipers - These are relatively rare actually and it's possible you can go through the entire game without realizing they exist. But they do, and they're fearsome if used properly. They have small unit sizes and have gigantic vision ranges, which is nice. Most of them are meant to kill off enemy infantry without the enemy even realizing. However, there is one guy... Canadian... who has an anti-vehicle sniper rifle. Not only can he slowly kill off your armoured troops, but he can also... shoot... HELICOPTERS. Yup. Not joking though, you really won't know what's killing your guys as there's no bullet trail or anything.