Instructions
Select "Normal Mode" from the main menu. In this game mode, you can take as much time as you want before every move, meaning the game is only over if there are no more moves possible.
Visualize your moves before making them. With unlimited time to decide your next play, it isn't necessary to go with the first one you see available. Look at all of your options on the board, and see where the most like-colored gems (those not affected by your potential set) will fall near each other. Likewise, never make a move if you can't tell whether or not it will open you up to another.
Fill your bonus bar by setting off combos and cascades with lower gems. The more gems you eliminate on the bottom rows, the more opportunities you'll have for new gems to set off combos throughout the board. Your first combo is worth two times the standard points and, with each successive combo, the multiplier increases. When your bonus bar is full, you will enter a new level, adding an overall 0.5 multiplier to every score.