Engage the players by giving them enough but not too much information to work on (as stated before) keeping in mind the interests of both the player and that of their characters. In the very least, try to keep them asking questions. As long as you have some applicable tidbits and details in your notes and/or keep improvising plausible answers, the exchange continues just try to keep continuity and coherence in mind. In the long run continuity and coherence become almost essential especially if the GM does have an ending for the campaign in mind.

This improvisation technique, which I like to call Spin Technique, is highly useful and in my estimation one of the most important skills a GM can have. It relies on the ability of the GM to fill in details in answer to the players’ questions and on the GM’s ability to spin a short yarn in order to coax the players into asking questions in order to propel the game forward and to essentially “kick-start” it after it has begun to stagnate. Essentially the GM is putting a ‘spin’ on anything they can to feed energy back into the game.

The spin technique also deals with “spinning” a mundane object or dull scene into something more interesting for the players. It emphasizes improvisation as much as imagination and descriptive ability on the part of the GM but it also emphasizes in keeping the exposition short. This technique is useful to the GM when the players reach an avenue which has not necessarily yet been defined, they are simply not asking questions (i.e. exploring), and/or the game is at a low point (typically the group is travelling, shopping, or trying to figure out where to settle down for the night, etc.).

The actual spin-technique itself consists of a quick sketch of a scene, any details to fix the setting in the players’ minds (allusions to the local religion, natives, local legends or tales known to the players), focus on any characters or plot happening, keep it brief, and fill in any other information necessary for the game on the fly. It’s a brief burst of information in response to the players’ actions/inaction and/or inquiries using what may already be present in the current scene.

The spin technique is simply a methodology to keep the game in the sweet-spot. The sweet-spot being where there are vigorous back-and-forth exchanges between the participants (Players and GM) and whenever the players are engaged and asking questions about the things within the game. This vital communication can dry up due to player disinterest, the GM ‘railroading’ the players, and the GM being ill-prepared or unable to improvise for whatever reason.

However, even a well-prepared GM will need to pause a bit to gather their thoughts and notes especially when caught off-guard, the trick is to not pause too long and if the players are still throwing out questions the GM should try to play off of those to reduce down-time as much as possible. Remember one of the most important points in keeping the game flowing is to give the players something to work with and likewise they can also give back the same ability to the GM. The impetus is still on the GM to prevent stagnation, whenever the flow of information dries up gets repetitive, or the exchanges stop or become one-sided the game is in danger of becoming a slog.

Two more common and time-tested techniques to minimize this stagnancy are simply “fast-forwarding” time (glancing over long stretches of uneventful travel) and introducing a random encounter. Both options are fine but doing either too often will also tend to drag down the game as it can become repetitive and reduce opportunities for the players to explore the game world and further engage with it. Basically, mixing it up and using any one of these techniques when most appropriate (or as a matter of group consensus) is probably a good idea.

Now this does not mean that a GM should constantly be throwing out encounters at PCs never allowing them to stand still even for a moment, even PC’s need some down-time, some time to breathe. Even lulls in the action can be used by the GM to the advantage of the overall campaign.