I've found that one of the fastest ways I've been able to learn new things and remember them is by teaching other people what I learned.
I may understand something and try it out, but it may just remain exactly what it is. It could be a solution to a problem I've been having for a while, and I found something online that worked for this scenario, and I moved on. But I've found if you then relate this story, you are forced to put it in your own words, describing what you think the issue was and your hypothesis for why the solution worked. You may get new insights into other problems that you're having, or at the very least, have a better vocabulary to find solutions to problems down the line.
If you shared what you learn, you also get the amazing opportunity to help someone else that might be working on a similar problem, and what you shared just gave them the last link to solve it. On top of that, you start a conversation with other people, saying what worked and what didn't; I've had many people respond to problems I've had with other solutions or related information that I would never have come to on my own! On top of this, you are showing yourself to be someone who wants to go to new heights and not afraid to say, "I don't know."
In my own learning, I've spent 6+ hours trying to figure out how to get a machine running, and there was a single problem that I could not for the life of me figure out. I eventually gave up and sat down to write about what I learned and did that day, only for the solution to come to me in the middle of my second sentence. It was so obvious and yet something I hadn't considered at all, and I only was putting my thoughts into words to share online!
Key takeaways:
1) You can better understand new ideas by teaching those to other people
2) Sharing your experience not only helps others but also opens other's to share their experience
3) Writing what you did, even if it's an open problem, shows you to be someone that wants to learn
4) Formulating your thoughts into words may give you the solution on its own!