Use a tarp or some other barrier to block the wind that causes the tree to creak. This may not be practical, depending on where the wind is coming from and how tall the tree is. But even parking a car near the tree may redirect enough wind that the tree doesn't creak as much.
Trim the tree's branches, so wind can flow through the tree more easily instead of pushing against it. If the tree has fewer branches and leaves, it won't be pushed as easily by the wind, and creaking should be reduced.
Drill a metal bracket into the area of the tree trunk that seems to be creaking. The bracket can help reinforce the trunk so it doesn't bend in that section, reducing the creaking.
Cut the tree much shorter, so wind will go over it instead of pushing against it. A shorter trunk won't bend, and the creaking problem should be eliminated. However, cutting the tree shorter may kill it.
Remove the tree, if the creaking continues.