Have characters but no plot
Question: I have these three characters that I really like and really want to use but I have no plot ideas for any of them. I've tried to come up with something and, thus far, have not been able to. Any tips on maybe ways to flesh out the characters or plots would be great.
About 20% of writers start with characters rather than plot.
Some people do a process of envisioning these characters in different situations and at different times in their lives and seeing how they interact - until a plot emerges.
Or, if you want a more direct approach...
Brainstorm possible ideas for the biggest crisis any or all of these characters could face at some point in their lives. What would challenge them? What might force them to face their limitations or their inner demons?
Maybe it's a person who enters their lives. Maybe it's an event beyond their control. Something that disrupts their world.
You might then apply a dramatic structure to each possible crisis you come up with...
Part one: How does it begin?
Part two: How does it get worse?
Part three: How are things forced to a crisis? Do they decide to change in order to meet this crisis?
Part four: How does it work out in the end?
If you find a crisis that really appeals to you, the next step might be to brainstorm ideas for the 8 essential plot elements, as they would apply to your chosen crisis.
See this article on how to do this...
Since you have three characters, one will likely be the main character (the one whose decision at the climax determines how the crisis will be resolved). Consider if one of the other two would make a good impact character - a character who can offer the main character an example of a different way of doing things (so he/she will consider changing).
Best of luck.