So your standing there, the conversation just died down and your thinking in your head, "OMG what now, what do i say, i gotta say something, but what?"....
There is a good tool i learned that will help here. It will help fill gaps and eventually eliminate them and help you guide the convo and control the frame.
I honestly learned this as a sales person a few years back, and have used it ever since but now i have applied a name to it and a conceptual definition behind it.
LEADING QUESTIONS.
What are these?
They are questions you can ask someone that:
1) Do not display too much intrest
2) Solicit information from them that can be used by you
3) Have a deeper purpose and use other then to have the other person talk.
So in essence what a leading question accomplishes is that it makes the target of the question reliquesh information to you that you can then use to start or continue a conversation or thread.
The biggest example, one that many of us already employ is...
"How do you all know each other?"
This question is not asked because your deeply intrested in how they know each other. Its value comes from the ability to use it not only to craft further convo but so you know what social boundries your dealing with.
Its a LEADING QUESTION because it leads to further convo. You might follow it up by telling them you knew they were best friends etc etc, or maybe they went to a school you know people at or went to yourself, maybe they grew up in a nieghborhood like you and your buddies....it all leads to you being able to talk and converse further on.
The common mistake made is that people use worn out questions like, "What do you do for work?". These are NOT leading questions because they show too much intrest, and typically have no more purpose then having the other person speak to fill time.
So how do you generate Leading Questions?
Its actually easier then it seems. They almost never apear to be relevant to the last or current topic of convo, so dont worry about making them aplicable to something. Just make sure that if your asking it the information can be used to talk about something you want to talk about.
For instance....
"Are you (guys) from this area?"
While this may not seem like a great question, its not all that bad. If you use it in a place your not from (say when you go outta town) it allows you to talk about you NOT being from that area, and they can either directly relate or show intrest in where your from. If you use it in the place you are from and they are not, instant convo...if your both from that place you have a commonality and can talk shortly about some of the things you like or dislike in the area.
Others that come to mind are along the lines of...
"Is this place usually like this?"
"Have you ever been to X place?"
"Have you ever done X thing?" (think sports/activites not sex, dirty minds

)
"If you could go one place, what would it be?"
"Whats the collest concert youve ever been to?"
...etc
So basically any question you aks that will allow you to take that in some direction...
Just for shits and giggles ill randomly pick one...say the concert question. I would immediatly after his or her brief answer go into talking about the concerts ive been to, goofy stuff that happened there...then go into talking about music i like etc.
So thats my post on "Leading Questions". Keep in mind though you dont want to exhaust these unless you need them. First use them only if things go silent...start using them enough and youll find yourself incorporating them into your conversations to smoothly transition topics and keep things flowing.
I generally uniterupted can "buffer" ahead in a convo about 30-60 seconds and plan for what im gonna say, because i use leading questions knowing that i wana talk about something. Of course i dont rely on this planning ahead but it helps a good part of the time.