You don't have to create an application, your product could be a book. IMO it is easier to make and to promote.
I've read a book I really like called "Marketing for Developers": http://devmarketing.xyz
I've read a book I really like called "Marketing for Developers": http://devmarketing.xyz
True. Writing an eBook is a lot easier than software.
But what I really want to do is help out an already established website with existing traffic. Rather than build my own from scratch.
So many open source projects would benefit from some good marketing.