I would say that most of the time, if the individual is not exceptional at something (in other words incredibly hard to find someone with those skills) they are looking for a people who fit in with their team, their culture and someone with a fantastic work ethic.
If I was looking for work as an Elixir dev I would do all/some of the following as a starting point…
- Read all the Elixir books and go through the best courses
- Build some things in Elixir
- Ask myself what kind of person the company I want to work for is looking for (and what kind of company I want to work for)
If you want to go beyond that, and feel you can be at the top of your game…
- Create a popular tool or framework such as Phoenix, Nerves, Lumen, etc
If you want to take a different approach, you could go through all the #community:elixir-jobs postings to see if a common theme is present… or even get in touch with a few and ask if there was anything in particular that would make any prospective candidates stand out. (Personally I think knowing OTP well would prove very beneficial.)
But ultimately I would say just be yourself and focus on what kind of developer you want to be, and what kind of company you would love to work for… everything else should just fall in to place 
