As part of university I had to finish a couple of online courses. I eventually created a system that helped me to learn the content and also finish the course within a week. All this is best done on a laptop, though I've watched some of the videos on mobile while commuting.
1. Set aside enough time for the module
As much as I'm speeding up my learning, it still took me quite a while because I wanted to learn, not skim through it. I spent a couple hours each day anyway to complete the different tasks. My goal was usually one module a day.
2. Download the extension Video Speed Controller and speed up the videos
Video Speed Controller is a browser extension that lets you speed up any video you see. It's been a lifesaver for me. I'm usually putting courses at about 2.5x or 3-4x depending on the difficulty of the module. Sometimes, I just read the subtitles - I'm way more of a visual learner and that helps me process content quickly. Do note that subtitles may 'lag' at higher speeds (especially on YouTube); you might need to manually adjust the video speed with built-in speed forwarders (like those found in YouTube or Coursera videos) as well to 'sync up' the subs.
3. Open up the knowledge checkpoint page on a new tab
These would be the mini quizzes you'd need to pass in each section. I would usually take a look at the questions first and keep them in mind before I start watching the videos.
4. Speed up the videos and look for the part in the video that answers the questions
The questions tell me what to look out for and honestly? Gets me excited for the content. As the video progresses, I'd fill in my answers for the different questions. I've found that this helps me pass the quizzes more quickly. Of course I would also think about the content and pause the video if I needed time to digest.
5. For quizzes you don't pass, keep track of your answers
I kept track of my mistakes in a .txt file I had opened. That way I know not to make the same mistake again, and it helps me to eliminate the wrong answers too.
6. For peer-reviewed assignments, timebox your attempt
For some of the solutions it was hard to get an answer. So I would make an attempt and limit myself to maybe an hour to complete it. I would then check my answers with the solution key before correcting them and resubmitting. The right answers were sometimes not something that I could have come up with on my own no matter how much I thought about it; I'd just save time and check with the answer. Because I already made an attempt, I was still learning from the assignment.
Congratulations! You just supercharged your learning and saved yourself a lot of time. Happy learning.