Alrighty so this campaign is pretty damn easy on Hard, nothing in particular should give you too much hassle, though there are three points I would like to bring up so you are aware of it;
1: The first War story where you are a tank driver. Take this one slow and steady, just like everything else but I think it's probably harder here than what the foot sections are, most things take you down VERY quickly if you are not careful.
2: Just make sure you are doing it on Hard, for whatever reason my difficulty reset a couple of times during the campaign so just before you launch a new war story make sure that it is set to hard.
Overall a pretty easy, breezy campaign to do on the hardest. but in the wise words of the Aussie from the Gallipoli campaign: "Don't be a hero kid"
Give 'em hell.