There's no better place to start than my personal favorite so far- Colonel Straken. He's a badass colonel in the Imperial Guard- er, Astra Militarum who fought for many years as a Catachan jungle fighter. Enough fluff, let's crunch!
In the realm of core set warlords, he's more or less par for the course in his basic stats. 2 attack and 6 hitpoints is (fittingly) a bit more on the "fight-y" side of the Warlords, but the differences are relatively minor. His 7 starting cards and resources are also par for the course for every warlord in the core set.
His special ability, however, makes him very dangerous. He wants to be in the thick of the fighting, boosting other units into pure killing machines. For this reason, Straken should be committed to pivotal battles each and every turn- and he should be commanding an army! Be careful though, his ability makes him a prime target for the enemy as bloodying him severely reduces your force capabilities.
Straken's Command Squad (4x) is pretty solid. With 4 copies in your deck, it needs to be! 2/2 is respectable, but not exactly awe inspiring. But when paired with Straken, your enemy is faced with a nasty prospect. Here's a relatively weak unit that will be hitting for 3 with Straken nearby... and if you kill them, they're replaced by a Guard token (which is a 1/2)! Even the guard token will be attacking for 2 with Straken. For a relatively low cost and a decent ability, Straken's Command Squad is a solid core. Plus, dude in the picture has a rockin' stache and kind of looks like Apone. "Stay Frosty, marines!"
Omega Zero Command (1x) is a fantastic support card. Unfortunately, only 1 exist in the deck- I'd have 3 if I could! While the Guard (sorry, I just have trouble calling them Astra Militarum) under Straken's Leadership want to have a horde at pivotal battle planets, this card makes planning ahead nice. Win the command struggle at planets 2, and 3, and you're guaranteed a solid unit in the coming battles. The few times I've gotten this card on the board, it's been great! Plus, it's one more boost for the Conscripts. Good card, but with only one in the deck, it'd be hard to work into an overall strategy since you may or may not draw it.
Now Glorious Intervention (2x) I can get behind! With two copies in the deck, you're bound to see it at least once. Your know who makes a fine candidate for sacrificing? An exhausted Straken's Command Squad. Why? They go away, deal 2 damage, and then get replaced by a ready Guard token! Save this for a big bad attack, and you may turn the tides of battle.
Straken's Cunning (1x) is probably my least favorite of Straken's cards. It's not that it's bad, it's just that with only 1 in the deck, and how situational it is, it's a bit too random. Still, if you draw it, I suppose it's nice to have due to its flexibility. 3 armor is hard to come by, and that is probably the main way I would use this card unless I am having some real trouble with card draw.
I hope you've enjoyed this article, please sound off on the forums with any feedback- particularly if you disagree! I am very open to reinterpreting cards in new light, and these are my favorite so far.