I love to brainstorm...it's great to be able to toss ideas out and keep pushing the envelope. Every genre can play. And here's the secret...whether brainstorming a complex suspense plot, or a sweet romance, the key common element is CHARACTERS.
When I start to brainstorm, despite knowing I'll get to the plot eventually, I like to start with my heroine. What's she look like? What's her name? What's she do? Now to move onto the good stuff....what's her internal goal? How can I give her conflict in reaching that goal? What's her external goal? Can I use something of her internal issues to hamper her reaching her external goal? Hmmm.....now let me think of a hero. His goal, I think I'll make totally opposite of hers. Yeah, that'll be fun. His internal goal the exact opposite of hers. Oh, but for fun, let's make them both striving toward the same external goal. Hmmm....this could be interesting.
But let's back up a minute....heroine's internal issues....what in her past made her feel this way? Decide to have such an internal goal? Hmmm...let's take that and make it something the hero can't/or doesn't think he can accept. Oh, yeah, let's mess them up royally. Now let's jump into his backstory....why can't/won't hero accept this part of her past? Something happen to him--his family--a friend?
Now, having this, I normally fill out an indepth character synopsis on both heroine and hero. Ready to start plotting? Nope. We're just getting started.
In mystery/suspense, gotta have a villian. Often have them in other genres, too. So let's figure out who wants the same external goal, but would go about attaining it in a bad way. LOL Why does villian want it? What will he do to get it? What has he already done to succeed? Hmmm...now, he's painted as a really bad guy. Maybe should give him a couple of redeeming qualities. What happened in his past that caused him to be so ruthless? What horrors shaped him into doing what's wrong rather than what's right? Good. Now he's well rounded. I actually feel a twinge of sympathy for him. Hmmm. All looking good. Let's shake things up a bit. Let's kill the villian off. There's the crime for my book.
Villian was bad, but had a couple of redeeming qualities. So who wanted him dead, and why?
And that's going further into brainstorming secondary characters. Now once all my characters, complete with their issues, backstories, and GMC are complete, I try to draw lines of connection between them. Who is connected to whom by a secret--a past event--any kind of connection? I try to keep pushing and going until my "graph" looks like it's sitting on a spider's web because of all the lines of connection.
Brainstorming...it can take you places! Try it!