A reader question: What is the best way to set up a series when you may only be able to sell the first book? Should I tell agents it's a series? And how cliff hangery of an ending should one do if there may be a chance that book one will have to stand alone?
When I submitted Magic Lost, Trouble Found to agents, I told them flat-out that it was "the first novel in my fantasy detective series." I did this because: one, it actually is a series; and two, in genre fiction, agents and editors (and readers) typically love series. Series are common in genre fiction, so don't hide the fact that you're writing one.
But at the same time, only pitch one book at a time. Once you've signed on the dotted line with an agent, then you can discuss whether you're ready to put the second or even third book on the table in a package deal to a publisher. This is where your agent's industry expertise (and knowing the editors at the various publishing houses) comes in. Typically you'll need a plot synopsis and the first few chapters to sell a second book along with the first. In my case, Armed & Magical sold along with MLTF as a two-book deal based on a synopsis alone.
This probably goes without saying, but before you start sending out those agent query letters, you must have a complete manuscript. There is no getting around that. Your book needs to be complete and as tight as possible and as good as you can make it before you start querying agents. When they request a full, you gotta have a full to send them.
And I told Kristin (my fabu agent) in my query letter that MLTF was my first novel. Don't be apologetic or beat around the bush with this fact; come right out and say it. Heck, everyone has to start somewhere.
As to a cliff-hanger ending for what may be a series -- I always try to wrap up all of the action that has taken place in that book. I don't like loose plot threads as a reader, so I try to write a tidy book. But at the same time, I set up the next book by having the ending raise a few more questions, so that it's obvious or at least apparent that there will be another book to follow.