Hey all, not really breaking our very, very long hiatus here, but I thought I might as well share this. I posted it as a quick-start advice guide to the Imperial Guard over on the IGMB, but thought I might as well add it here too.
-DO expect your troops to die. We are but men of flesh and blood, not Iron and Adamantium (some of our SCs being exceptions). Keeping this in mind, you can either try to combat this by taking more men, or by making your men more durable. Each has it's limits. For the first, remember that your Guardsmen still burn, and will still break and run if they don't have a Commissar looking over their shoulder. Remember to support your morale and space your men against those templates. For increasing durability, remember that there reaches a point when we'll still die. Upgrading a CCS with Carapace or a Medic is fine, but both is usually overkill for the points cost.
-DO expect your men to miss. Take note of this, and plan your list accordingly. Units with BS 3 should be given GLs, Flamers, and templates whenever possible, and be taken en emasse whenever not. Units with BS 4 should be given things like Meltas or Plasma if and when possible, although you should always remember that more is better here too, and pack your Vets full of SWs. The "Swamp it with fire" principle should apply to just about everything in your army as well. The only thing better then a lascannon is three of them, and the only thing better then that is when they're twin linked.
-DO support your army. Don't take one unit of ranged AT, and one unit of close AT, and call it good. Don't send one Chimera or Hellhound out on it's own. The Imperial Guard is built upon a militarized version of the Buddy System, and you should always try to have at least two units in an army that can accomplish the same goal. The cheapest way to do this is by taking multi role units. For instance, the Vendetta is good ranged AT, and provides you with mobility. Plasma Vets are great at killing tough targets and popping light tanks (or heavy if they get behind them), AND count as a troop choice.
-DON'T hand out wargear like candy and expect to get a good return on your investment. 10-15pts should be your limit on wargear cost per trooper, ranging up to 20 on occasion. Taking 30pts of wargear on a single model is asking for trouble, unless it is a Commander of some kind, or said upgrade actually helps everyone, not just that one model (like a Medic or Standard). Also consider how often you will be using it. A Power Sword in a Plasma CCS might offer some peace of mind if you do get charged, but most of the time it will be a points sink.
-DON'T leave cover unless in a transport. Cover is the lifeblood of this game, especially for us. No matter how good your armour save is, you should be either in a metal box, or in cover if at all possible, and even those metal boxes should be in cover if you can swing that. Chimeras are cheap, and they have Smoke Launchers for a reason.
-DON'T be afraid to sacrifice men. This goes hand in hand with the first DO. Your men will die, that's a fact. The question is, at one point can they die and still have been worth it? For instance, I consider my Vets to be expendable, and use them aggressively, which will usually net me a few MCs, Tanks, HQs, etc before they die, which I consider worth the cost. Being that aggressive with them can actually cripple an army so effectively that they can't hit back at your Vets, meaning they essentially become a "Do or Die unit". Remember though, there is a fine line between aggressiveness and suicide. Tossing your units out where they will be slaughtered won't do you any good. So, while you should be prepared to have your men die, helping it happen faster is not productive.
-DON'T expect to win by the prowess of your men. We are not the best shots. We are not the best hand to hand fighters. We are not the bravest. Don't try and have your Captain fence with a Chapter Master or Chaos Lord. Have him call up 30 of his friends and beat the guy to death with numbers. Likewise, Commissars are a nice way to keep your men from running when the going gets tough. Always remember the situations in which your men are weak, and try to tweak the odds of success there more in your favor.
-DON'T mix roles in units. It may be tempting to give a PCS a pair of Meltas, a Flamer, and a Plasma Gun, and send them on their way, but please don't. It's much better to have that unit dedicated to a single roll (AT, AI, etc) and have them be good at it. We can afford to take multiple squads and kit them out for special roles, instead of having to have one unit do everything. This may seem at odds with what I said earlier in the "Support" part, but it's not. Consider the Vendetta. It has the ability to transport without harming it's AT ability. Those Plasma Vets can do all of those roles well, but I shouldn't expect them to deal with mobs or heavy armour, and I would be better served grabbing a unit of Melta Vets in addition to the Plasma Vets, as opposed to trying to make the Plasma Vets effective against Land Raiders. There are exceptions to this rule (like an HF and 3 Meltas in a PCS), but they are rare, and usually mutually support one another without hindering the effectiveness of the squad.
-DON'T judge the worth of a unit simply be the damage it puts out. My Hellhound usually doesn't make it's points back, but it draws absurd amounts of fire and generally causes Mayhem in the enemy ranks, essentially nailing down a portion of the enemy line while they cope with it. Similarly, my Vendetta, although it's kill record is impressive, has served me more as a transport and distraction then as a tank killer. Platoons usually won't make their points back either, but they're durable, can score, and will tie down CC squads like nothing else. All that said, though, do try to take a unit that can at least make a decent showing of itself on the table no matter what. Ogryn may have lots of wounds, but getting them rapid fired to death before they even fire a shot or take a punch is just a waste.
Lastly, remember to try things out for yourself, have fun, and don't be afraid to ask your opponent for advice. This is a game, after all, and the main purpose is to have fun.