Begin with facts that have one meaning
Word length and exact positions are the clearest constraints because they have little room for interpretation. Enter those first. A confirmed beginning, ending or centered fragment comes next.
Add flexible clues after the shape is visible
Required and excluded letters are useful, but they do not describe a complete pattern by themselves. Add them after fixed placements so you can see how they affect an already meaningful result list.
- Choose the exact length.
- Fill known positions.
- Add a confirmed beginning, middle or ending.
- Require letters that may appear anywhere.
- Leave out letters that cannot appear.
Change one uncertain clue at a time
When no words match, remove the least reliable clue and search again. Changing several fields at once may produce results, but it hides which assumption caused the conflict.