I spoke about using the snowball-method for querying in a few writer groups and people were surprised and had never considered doing it. So I thought I'd share how it works and also why I do it.
At the beginning of the querying process, you have a certain number of agents you contact. Let's say 5 to 10. At this point you're still very hopeful and more or less happy with your life. You believe in your manuscript, because why else would you put it out there?
How likely is that one of these first five people will take you on? I'll venture to say: Highly unlikely. So by sending out these first five queries you are setting yourself up for five rejections.
Now, here's a thing about me: I don't cope well with rejections. They make me question everything. Not only the quality of the manuscript, not whether this story is any good, but much more fundamental: Am I a crappy writer? Should I even be doing this? Am I worthy to be a human walking this earth if anything I produce is shite?
My brain after a rejection is not a good place. But I have found a way to curl up and cry in a corner and that is: For each rejection I get, I immediately (on the same day, if not in the same hour) send out two more queries. This means my agent-list is much longer than these initial five from the beginning, so I don't have to spend hours researching new people whose MSWL my story fits, but I have a spreadsheet with names and requirements right there on my desktop from the beginning.
So the moment I get a rejection, I let myself wallow in my little hole of self-hatred for a bit and then I sit down and send out two more queries. In case of our starting number being five, all of them come back as rejections, you will have sent out 15 total already. As usually, rejections don't all come on the same day, even after this process has been repeated a couple of times, it still doesn't get overwhelming. And it keeps you in the game, it keeps you running, it keeps you doing the thing even though the thing is not fun and not getting any nicer with time.
I am far from being a writing-and-querying guru, I am just sharing this, because it works for me and it stops me from giving up too early. With the snowball-method you always keep a few queries in the run. And the more rejections you get, the more queries you will send out. The only thing you need to make sure before you start is that you have a substantial list of people you think might be a good fit for your novel. And that there's enough chocolate to help you through the small bouts of wallowing after each rejection.
Good luck!