Well  a mainstay of steampunk is the runaway high society female who becomes a kickbutt.  I personally think you should put in a thief or two, but that's really your choice. 

I think gypsies are good.  Also fencing people.  And apprentices/factory workers.  I would ask Theo on this subject.

Two of my favorite steampunk fantasies have the same sub genere, which I realized today in the car and it really freaked me out. Meaning [main character here] thinks they have a mysterious dises that limits them and they meet [second main here] and are launched into an adventure when they learn somewhere in the plot line that they are destined for greatness. Or something like that.

Someone with a top hat. That's all you need in a steampunk thing. 

Great. Thanks guys!

try basing it on people you know but using different names so it doesn't give away who you are

sorry.  i also meant to say who they are in my other comment

Okay, so maybe start an outline. Write down: CHARACTERS, PLOT, SCENE, PROBLEM, SOLUTION. Then think of some vague ideas and write them down. If you want to change anything later that's OK! Ideas get scrapped, it's part of the writing process. Some tips... 1. Don't make it too long or complicated. It gets boring and hard to understand. 2. Think of memorable ideas. Character names, scenes, and plots can have unusual twists that make it memorable to the reader. 3. READ! Reading a good book always helps me think of writing ideas. You can use the plot, style, vocabulary, etc. to help you think of your own ideas. I hope this helps! Take a deep breath and begin. Writing a story, while can be tricky, is an overall fun and exciting activity!