I know it sounds a little silly, but I would suggest finding something you want to do, then learning how to do it. Some good candidates off the top of my head might be to edit pictures, audio, or video; to produce a resume with LibreOffice; to design a website with Kompozer.
When I started, I played around on my brand new Linux installation for a while kind of aimlessly, then got inspired by a conversation on a business trip to use that computer to self-host my website. It's amazing how easy learning becomes when you have a goal.
Here are three resources I have found useful.
. It's oriented to Ubuntu, but it's full of good info oriented towards beginner and intermediate users. I was no longer a beginner when I discovered it, but I still learned stuff.
. Machtelt Garrels Intro to Linux.
. Slackware oriented, but excellent on the basics, such as file structure, permissions, and the like.
I also found that just adding the word "linux" to a websearch would narrow the results wonderfully.