Practicing

[arf]

playing 40 lines will only teach you speed. I have a friend that has been playing 40 lines on Blockbox for the past year and he has a 32 second time right now I believe, but as far as his skills in the multiplayer aspect, he still loses most of the time to players that have around a 50 second 40 lines time.

multiplayer with opponents that are just half a step in skill above you would probably make for the best practice. it teaches you how to handle pressure, teaches you how to get used to maintaining a higher speed, and it forces you to try your hand at downstacking. also, just watching the elite players play against each other can be very valuable. watch how they use their pieces and how they involve downstacking into their game.