It took me some time to get started. But that's probably because I had no HTML/CSS experience.
Spend some time fully learning HTML/CSS. No need to delve into the deep aspects of CSS though, just basic formatting will help.
First thing I did was make a login system as suggested above. I didn't learn any of the fundamentals before doing so, literally just pulled up a tutorial without knowing any of the basics. That was a stupid move on my behalf but it still ended up working
It took 3-4 hours to get the site login done, and then I started learning the fundamentals

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I probably built my first advanced blog in around about 2-3 weeks. I didn't follow any specific course but just thought about how a blog should work, admin panel and whatnot. Planned it out, got to work. Soon enough I had a decently functioning site
An advanced project I did was making a site for a game that was popular in the blockchain community some time back. I probably only spent 30-40 actual work hours on it, but it turned out great. I would love to be able to show you the site if I could but I deleted it after the game didn't have many users left. I learnt about curl and interacting with APIs whilst working on this project, so it was very helpful.
I highly recommend working hands-on with PHP. Not just reading books and doing small exercises.
Design-wise, codepen is your best friend
