So I've been reading a lot of 40K novels lately, and they've all been really helpful, though the ones focusing on Marines have done the most of course. I was wondering what other sorts of inspiration people have been able to find, not just from Black Library stuff, but other sources as well, and what they've done with it.
For a couple of the things I've latched on to, it's mostly been the small things, little details that add a lot of flavour by the way they emphasise that the Astartes are a warrior fraternity who take their heritage, as well as their honour, very seriously.
Flight of the Eisenstein mostly in the form of how wargear was treated. We've always known that the Space Marines 'recycled' their equipement, passing along Bolters and Power Armour as old bearers died, but something I never would have considered before is how the names of all the previous bearers would be engraved in to the casing of a Bolter, as noted by Captain Garro, when he is issued a replacement, and spots a the name of a recently fallen Battle-Brother from his company. Or how wielding the power sword Libertas is considered a great honour in and of itself, far beyond the raw might of the weapon.
While another example is Helreach, which I just started recently, and how it never occured to me that some Chapters of the Space Marines might ise a term like "Knights" for their brothers. Not to mention the insight it would give in to the Black Templars themselves, as a Chapter.