Keep a close look on the bar showing the next three balls to be dropped onto the game board.
Try to keep at least a half of the game board cleared. Letting the balls to pile up will almost certainly lead to a loss.
To make your game easier always keep more than one line of the same balls ready for clearing.
Build up lines near the border, so you have more room for navigating the game pieces around in the middle.
Try to keep more than three almost completed lines existing on the game board at all times.
Almost completed means that they are four same balls in length, and only one ball remains until their completion.
When moving a ball away to make room for another row, move it into a suitable place.
When positioning balls for a line, get the balls farthest from the row in place first (they have the best chance of getting blocked away).
Long rows are rewarded with a lot more points than short lines. Try to build diagonal lines, too.