Hi Bonnie! Glad to help out.
A synopsis for a novel (some people refer to it as an outline) is written in present tense. I usually type mine single-spaced, so when it's submitted by my agent, it is readily distinguishable from the chapters that she submits.
Synopses that are written for submission should be as short as they can and still tell the ENTIRE story. Don't be coy and say "And to find out what happens at the end...read the manuscript!" (People have indeed done this and it really annoys editors or agents.)
Give about the amount of detail in a synopsis for submission (as opposed to one that you, the writer, might write for your own use in writing your novel) as you'd use in describing a good movie to a good friend. You don't want to tell every single detail, but you want the plot to flow along in a concise, yet understandable fashion. You shouldn't include minor details of characterization or subplots. You really want to confine yourself pretty much to the main plot and what feeds into it.
When I'm writing a synopsis, I imagine my audience as a group of wriggly cub scouts around a campfire. They have short attention spans, and your narrative has to be dynamic and intrinsically exciting to keep them "hooked" on the story that is unfolding.
I usually figure on writing approximately a paragraph per chapter, unless the chapters contain a lot of crucial action, like the climactic action at the end of a novel.
When I write a synopsis to use for my own purposes in writing a story, to make sure I have everything firmly in mind and won't write myself into a corner, I write a MUCH longer, more detailed one than the one I'd write to submit to an editor.
Well, that's about all I can think of to say on the subject at the moment. Tomorrow I'll dig up a submission synopsis from an old book and post a paragraph or two here, if you think that would be helpful...?
Since today's post was all about writing, no Writing Tip tonight!
-Ann C. Crispin