A recent post on powershell.org – https://powershell.org/2017/06/22/taking-powershell-to-the-next-level/ – gave this path for learning PowerShell and becoming more proficient
Books:
Learn Powershell In A Month of Lunches
Learn Powershell Toolmaking in a month of Lunches
Windows Powershell In Action 3rd Edition
Online:
Advanced Tools And Scripting with Powershell 3.0 Jump Start
Writing Powershell Powershell DSC Resources And Configuration
Demo Code
To that list I’d add
Books: PowerShell in Depth 2nd edition – read it before PowerShell in Action
In parallel with the books and online courses find an area that you can work in – Active directory, Exchange, Windows admin, Hyper-V, SharePoint, SQL Server or whatever and start solving practical problems. You’ll learn more fro doing that than all the books you’ll ever read