What's really in those swamps? What're the names of those Bisclavret ports? Who runs Epinian? What's on the north side of Calabria? The source material is designed to be an outline of "adventure seeds" to get things going.
Every RPG has a "major theme", whether they think they do or not. In AD&D (published by TSR), the theme is to improve one's character by defeating stronger villains and garnering treasure. In Vampire: the Masquerade (published by White Wolf), the theme is the intrigue and horror in a modern-day setting. In Call of Cthulu (published by Chaosium), the theme is fighting an eternal struggle against almost insurmountable odds.
In Ironclaw, the PCs will represent the new "middle class". They have esoteric skills and abilities above the common unskilled laborers, and they have lots of expensive equipment. They're certainly not "lower class". However, their adventurous lifestyle makes it hard to hold and to administrate land, and they're not likely to be heirs to any thrones, much less even "blooded", so they're not "upper class" either.
The political situation in Calabria involves three "noble" houses in a "cold war" that revolves around a large "free" city. Often, nobles will have to employ the PCs for clandestine operations for which their own men are unusable for one reason or another. In addition, the new Guilds of Triskellian are rich people with political motivations but no "divine right" to take land, so they can't act too brazenly or they'll annoy the noble houses. Adventure scenarios can exploit these aspects to create scenarios of uncertainty and conflict.
When you write your adventures, remember that things usually happen because people decide they want them to happen. People lie, cheat, steal, hold grudges, and fall in love. When deciding the next big "events" or scenarios, make sure they "advance" the goals the NPCs.
Definitely do not have NPCs who throw their lives away by attacking the PCs without a clear goal in mind for doing so. Major NPCs may send minions to delay the PCs from their goal, or to finish them off for good. They should rarely put themselves at risk. Force the PCs to track them down into direct confrontations.
A good plot line is a three-step one: (1) NPC hatches complicated plot; (2) plot crosses PCs path who must interfere, (3) major NPCs draw PCs into conflict. This plot is usually a good one for gaming, because it forces the PCs to become involved of their own free will. Be prepared for what happens if the PCs don't interfere – have whatever the NPCs have in mind be antithetical to what the PCs like, perhaps even dynamic enough to alter the campaign.
Plot lines like this one are especially good because the NPCs have realizable, realistic goals … which doesn't necessarily mean just "killing the PCs". Plot lines like this one have NPCs who grow to hate our PCs, and who can use methods of conflict that aren't necessarily combat.
In Ironclaw, we designed our game to encourage Players to build characters who would have complex social conflicts. PCs can have disadvantages involving their personal honor, their social commitments, their senses of justice, and their obligations to the law. It's harder for the amoral, uncaring characters to get involved in "proactive" plots.
Some adventures are scenic tours where the plot line centers on the PCs travelling through some exotic locale where they meet the locals and tour the countryside, but there's little to do or to interact with. For example, an adventure where the PCs go to the Small Town, pick up the Sacred Object, and deliver it to the Other Spot, while meeting lots of people on the way but never really getting into any dramatic conflict. Sometimes this adventure adds a "Native Guide" who has all the necessary skills and preparation for the PCs to get through the place, making it a no-brainer.
Make sure that if you write up some exotic locale or colorful people that there's some sort of conflict with them, something that involves the PCs, either to get their assistance or to interact with them. Perhaps the Native Guide gets killed or captured. Perhaps he's corrupt or evil for some reason. Perhaps he isn't as competent as he thinks. Maybe the area has changed, such as new bandits have moved in, or some horrible monster. Toss the players a curve.
There's a strong temptation to write up NPCs that are really "cool". They have large legions of unquestionably loyal followers. They command vast wealth. They are unrivaled spell-casters. They are unequalled sword-masters. And, worst of all, they're incredibly necessary to the adventure plot, on the PC's side. One sometimes wonders why, if they are this qualified, they don't do everything themselves.
Don't let your major NPCs over-shadow the PCs. Let the PCs keep guessing as to their true power level. The Ironclaw system is designed to allow for levels of specialization … so have your NPCs specialized in a very narrow niche, which the PCs can't match since they're such generalists. Don't write adventures that make a "cool" NPCs intervention mandatory, especially if those NPCs might get into combat. Plan for different endings.
Don't confuse dice rolling with conflict management. Don't have adventures that will come to an absolute, grinding halt if the PCs miss a skill roll. Adventures of this type include ones where the PCs must make a Research roll at the library, or they must make that roll to find the secret door, or they must know enough about Metallurgy to divine the location the scepter came from, etc.
The major problem with this sort of adventure is not that the PCs might fail those rolls – it's that, if the PCs figure out it's this kind of adventure, then they may realize they don't really need to think their way through it. Either their die rolls will decide the plot, or some specialty NPC will show up and lead them by the nose to the next part.
A good adventure will have "opportunity costs" and risks that keep the PCs on their toes. One good way around this bug is to have a "simple" solution that requires specialty skills (whose rolls can fail), and a "complex" solution that requires the PCs to jump through a few hoops but is otherwise solve-able. This will encourage the PCs to try to think of ways around that complex, difficult way – and encouraging the PCs to come up with creative solutions to their dilemmas is what good role-playing is about.