Descrição
So as it turns out, there's a decent amount to learn to get good at this mode. Haven't done much progress in hard mode, but at least in easy mode, I have managed to learn to recognise enough patterns to be able to throw all clears fast enough for a clear. I won't put all my complete detail in here, but here's the general gist of my strategies:
For one, even though this is not using a bag-type randomiser (trust me the mode would be solved otherwise so this is a good thing), it's still using a fair randomiser on only 5 pieces, so you will quite often get in a situation where you're dealt one of every piece in some order. You can learn a few different setups to deal with different piece orders as they come.
Another useful strategy is to divide your stack into smaller rectangles to be filled individually. If you get two Os, Ls, or Js you can turn them into a 2x4, LJO, LLO, JJO, and sometimes JTT or LTT can be turned into a 3x4, and I of course can count as a 1x4. When you take line clears into account, you can also use LJT to fill a 3x3, and TJ or TL to fill a 2x4.
And lastly, although the All Clear finder that helps you out in the first 25 All Clears is limited in its placements, it can still be useful to learn how to deal with particular unusual situations, so it is possible to learn something from it. Pay attention, and try to remember if something particularly nasty comes up.