The suggestions on their website are all good https://julialang.org/learning/
I also followed this course : https://www.coursera.org/learn/julia-programming
You also find a lot of interesting videos on Youtube but be careful....Julia is a new language and it's still under heavy development so try to find updated videos!
I am using the language and i like it...it's a mixture between R(despite to the fact that R is not a programming language -.-) and Python.