If you have made it this far in this free super-casual Tetris guidebook, I congratulate you on graduating from the first steps.
This guide should have equipped you with sufficient skills to play Tetris reasonably well.
However, if you would like to advance to the next tier, I suggest reading my next book, How to Start Tetris: The Ultimate Beginner Guide. Its digital version is entirely free on my howtotetris.com website:

I have also made many chapters of at least 3 more intermediate and advanced Tetris guidebooks available for free on my website.
I also have free tutorial videos on my @GalactoidTetris YouTube Tetris channel.
If you desire to aspire to greater heights, the sky is the limit. I have prepared an entire course—the first in the world—that covers everything.
That is right: from Tetris elementary school to Tetris Ph.D!
I wish you the best of luck!
May you ascend to Tetris godhood one day!
Companion Websites and Resources
This book has 2 companion websites, a YouTube and Twitch channel (more information in the back matter). I also have other social media accounts.
My HowtoTetris website contains an errata page that catalogs all errors found in the book series, which I will update frequently.
I will also announce any major news on the book series there.