Move in Groups
Always move the marbles in groups of two or three. The rules allow you to move three marbles at a time as long as they are in a row. Take advantage of this rule as much as possible. Groups of two and three are able to knock marbles off the board and are less likely to be attacked. Lone marbles are sitting ducks waiting to be knocked off the board.
Get to the Center
Move the pieces to the center of the board. The center of the Abalone board is like the high ground of a battlefield. Having your pieces in the center requires your opponent to move around the edges of the board. The closer to the edge, the more likely you will be able to pick pieces off and knock them off the board.
Stay Together
Keep the marbles all together in a group. This may make progressing along the board slower as multiple moves are required to bring the rear marbles forward; however, this offers the best defensive strategy on the game. As a group, it is nearly impossible for your opponent to find an opening to try to knock your marbles off the game board without exposing his own marbles to the same fate.
Divide and Conquer
While you are trying to keep your marbles tightly grouped, move in such a way that requires your opponent to separate her marbles into smaller groupings. These smaller numbers are easy to knock off the board while limiting the opponent's ability to counter since the rest of her marbles are located elsewhere on the board.
Be Patient
Opportunities to knock an opponent's marble off the game board will arise during the course of the game. Some players will use a lone marble as bait to get you into a weaker position. Keep together, try to anticipate your opponent's moves and have a plan of attack. If you trap an opponent's marble, it will remain trapped later in the game when your opponent cannot counter your movements as well.