What do beginners struggle with?

What I found works 99% of the time (I have not yet encountered the 1%, so it might be 100% of the time)

In Lein, you add this to the vector of dependencies: [org-name/lib-name "0.1.1"]
In deps, you add this to the map of dependencies: org-name/lib-name {:mvn-version "0.1.1"}

And in Lein, sometimes you’ll just have lib-name, no org-name, so you can try: lib-name/lib-name {:mvn-version "0.1.1"}