I had a lot of trouble getting into PowerCLI. I knew some of the basic commands, but I never used it to do anything productive. The biggest site I managed had 150 VM's, and I could do most tasks quickly through the vSphere client.
Since then I've changed jobs, and now there's thousands of VM's to manage!
Coming into such a large environment, I've had to learn Powershell and PowerCLI out of necessity.
The thing that gave me the biggest kickstart, was watching Pluralsights's Play by Play: Discovering PowerShell with Mark Minasi.
This is like watching over the shoulder of a student learning how to use Powershell from an instructor as they discover how to use commands, and extend what they've learnt to other commands.
The discovery process is fantastic. It seems very organic, the way they use a command, and then see what else they can do using that same process.
Mark Minasi is excitedly animated, and enjoyable to watch. He's the type instructor you'd hope to get in person.
If learning Powershell has been on your todo list for a while, I highly recommend you watch Play by Play: Discovering PowerShell with Mark Minasi.
Pluralsight has given vExperts & MVP's free access to 1000's of courses. If you're not lucky enough to win access, I still think it's a worthwhile investment for $30 a month.