I can not give you more direct examples due to the forums rules,but I can help you figure things out yourself.
There are two things I'd recommend you to spend thinking about.
1) What is my message for my readers to get, what are thoughts and feelings I want to provoke in them?
For example, steam punk is usually basing itself off first industrial revolution and Victorian Era. And people were frightened of mechanization, there is also huge inventor spirit and enthusiasm which you can explore by maybe reading up some biographies of prominent and some less prominent scientists back then. Dig into history to find themes and morals. It does not have to be super complicated and deep.
2 ) How do you want it to end. This is very important to have in mind and it will help you direct your story once you get stuck.
Also, I have
bookmarked this tumblr post about steam punk few days ago, where you can find some things that might inspire you.