Take time to observe
In brief
A jump requires a starting marble, a marble to jump over and an empty hole beyond it. Before clearing a region, check how the remaining marbles will be able to leave it.
Prepare the landing space
A jump requires a starting marble, a marble to jump over and an empty hole beyond it. Before clearing a region, check how the remaining marbles will be able to leave it.
Avoid isolated marbles
A marble cut off from all the others may become impossible to remove. Keep opportunities for the groups to meet.
Work backward from the target
Imagine the final jump to the target, then the holes and marbles it requires. This backward reasoning can guide the final moves.