From zero to Gopher with Master Go.
Or deepen your concurrency skills with Concurrency Deep Dive.

Do not settle with half-baked courses that skim the language but do not dig into the details.
Master Go delivers the fundamentals that you need to become productive right away.

If you know Go already and want to become proficient in concurrent programming, Concurrency Deep Dive is for you.
Concurrency Deep Drive is included in Master Go and can also be purchased separately.