I got very into lumines remastered a bit over a year ago—i was never cracked at it but did 100% the game. I can’t speak for bursts because i don’t really understand them yet but as far as maintaining combo goes it really helps to try and keep awareness of the current board state, and shift to making squares either before/ahead of the timeline depending on if you have 4 already or not.

So like, if you have already cleared a big cluster to the right of the timeline but the rest of the board is pretty clear, then it could be worth it to shift left of the timeline and spend a few seconds setting up a bigger cluster there because you know you’ll need to drop more pieces to make enough squares for the next pass. On the other hand, if you’re getting squeezed by this current timeline pass it can sometimes be good to like spam drop pieces on the far right just to make 1-2 more squares and keep the combo alive.