On level 123 you should pick a small portion of the game field and stick to it. Slowly go from it to the left and right sides, clearing the rest of the field and completing the objectives. If you start doing random matches across the entire game field, all of the ice will fall down, and you may end up in a situation when there are no good moves to make.
Keep a close eye on the field, as it is essential that you do not miss a chance to create more power-ups! Do not rush into using them though – try to get a couple of power-ups close to each other and activate them in a single move. This will clear more space and will charge the Lightning power-up faster.