Responsive base apparel coming soon challenge solution

It helped me to learn the basics of -

1. flexbox
2. Elegant button styling(relatively most difficult part for me to place everything at the right spot)

Are there any suggestions on how to extract the most from these challenges? My approach usually:

1. I write the HTML and give it classes as much as I can see it might be needed.
2. I start with CSS, Font and then the overall layout, then styling the elements individually and at the end the media queries. I get stuck a lot and takes me almost 3-4 hours to reach a somewhat similar-looking page.
3. Then to learn I go to YouTube and see if someone has explained their solution and try to imitate them to correct the things I messed up badly.

What would be more mature approach to learning? This is certainly better than doing courses, but I feel I am learning slow? Or don't just want to be sure if it's the right direction...