Last session, I just started my homebrew campaign's second arc. I have a good foundation of material with several plot hooks. As things went, there was a whole lot of story and very little combat, which I felt was a refreshing change of scenery. Combat is fun and we all like to roll dice, but it can soak up a good chunk of a session's allotted time pretty easily. Since last session was rather light on combat, I got to lay out a lot of story material that I had prepared. In hindsight, I am surprised by just how much of my content I went through in a single session. We are ten sessions into this campaign and we've been doing it for nearly a year now, so you'd think I would be better at pacing (or maybe better at anticipating the group's pace) by now. Or do you think the fact that this was the first session of a new story arc had a lot to do with it?

We typically play about once per month and our sessions run 4-5 hours usually. I would like to hear from other experienced DMs on the way you pace your story so that you don't drag things too slowly, but also don't blow through your material too quickly. I don't feel like I'm doing anything specifically wrong, so this isn't meant to be that kind of a thread. I suppose I'm looking for tips on improving my delivery.

I have a horrible time with pace, you're not alone. I recall my players spent 5 days (in game) in a town which equated to almost 6 months in real life. There was another instance where it was the reverse, I had planned on making the story arc last a while and the players managed to cut the time in half. So, I've had similar thoughts to you and I've tried a few things. Here's a few ideas I had that might point you in a direction:

Players will get tunnel vision if you spend effort in detailing something, balance your descriptions to reduce the "snipe hunts" and accidental false leads. This is one of the things that we do without realizing it, we get excited about making a robust mental picture for or players and because we spent a little too much time on a particular shanty on the outskirts of town, the players will head straight for it. Try to find ways to make the descriptions similar throughout the session about everything, this way you can force the red herrings and not have the players wander off without purpose.

Have a plan of action before you begin the game, story beats, important NPCs, specific locations, etc. and stick to the plan as close as you can. I start every session with a note card that has anywhere from 3-5 specific things I want to happen in the game that night. My sessions last anywhere from 5-7 hours and in that time I generally let the players run around and do what they want reacting to what ever it is they're doing at the time. However, keyed to where they're starting the night is one bullet point, I make sure to start the night off with that, or have it happen shortly after we start. Then I track when there's a lull in the players' actions or they hit something that ties in to one of the next bullet points and hit the next beat. It's not perfect, but it has helped me make sure to move things along and not let the players stagnate due to not knowing what to do.

The last bit is kind of tricky as it doesn't work for all tables: curtail your, and your players', habit to side talk and tangent off into non-game related things. I have a very relaxed setting, I play in my dining room with a bunch of close friends. We are always tossing out puns, bad jokes, singing, talking about anything and everything, and it can really throw the pace of the game askew. I had to recognize this and start reigning my table in, not stopping it, but making sure to say "ok, back to the game" or something similar. Worst case scenario, like in the middle of combat, I'd simply give one of my players 3 chances to respond to my prompt, then move on. It only takes a couple times of doing this, and explaining it, to make sure that the table keeps at least one ear/eye on the table to know what's going on.

Hope this gives you a place to start, and happy gaming!

I do think that every time a new arc begins, a lot of story has to happen, particularly if your table is into the roleplaying element. Also, I think that part of what happens at that point is that you and your players are determining together which parts of your story world are going to be the "big ones" that people care about, and which ones are going to be vestigial to your main activities. Now that you have that information, I think that the next round will have a bit more action, and more importantly more engaging action. Pacing is always an issue in D&D, but it is not necessarily a bad thing if some sessions move more quickly and slowly than others. The only advice that I would give is to ask your players in advance which parts of the new story they want to explore, so you can develop those sections for next time and save time on threads the players don't plan to follow. Hope that helps.

Sincerely,

The DM who just built out a whole dungeon just to have his players spend the whole session kidnapping their coachman instead