Ekorren:
Follow-up question: Are there any tips or tricks on how to increase activity and progression in games where you don't have outside contact with your players?
Keep moving forward. Don't back up to correct things, even when an obvious mistake has been made. Note the mistake, if necessary, and try to do better next time.
As a player, don't block the ideas of other players as long as those players are acting in good faith. Instead, accept an idea as soon as possible and add on to it to improve it.
If you must block an idea, replace it with another one.
When you present a course of action, do so firmly, avoiding words like "suggest," "perhaps," "maybe." Those words invite blocking and negation, because they suggest doubt in the idea.
<quote Ekorren>I think that some of the stuff that have worked best for me have been more GM involvement in the scenes (including using NPCs as active participants when a scene is getting stale to ensure that it keeps going), and to delay the actions of idle players during combat scenes to make sure that system-intense action scenes progress quickly. It's important to communicate this with the players, though, to avoid having a scene feel railroaded.
I don't agree with NPCs as active participants, but I do agree with having slow characters delay, if the game allows for that.
I agree with communication with the players as well as solicitation of and strong consideration of their ideas about the game, even to the level of specific details. Submitting such ideas should be optional, but the GM should be open to them and accept and add on to them, encouraging others to do the same. This will ensure that what is happening and what is going to happen in the game will be things the players enjoy, which makes them more invested.
That idea bothers people who feel that it's the GM's job, and no one else's, to create details of the game, so it's important to communicate with the players about this approach.
<quote Ekorren>
Follow-up question: What are your tricks for maintaining interest/passion as a GM?
The aforementioned communication. If I know that what I'm presenting to the players are things they want to see in the game, then I'm more interested than if what I'm presenting might only interest me, or if it's designed merely to be broadly palatable to a random audience.