Search for the subject, not a mood
Useful search terms describe visible things.
Prepare
Begin with an entity and an action: a named telescope being assembled, or a person inspecting an electrical panel. Add a place or date when those details matter. Abstract words such as “innovation” often return unrelated visual metaphors.
Work through the decision
Inspect candidate captions and source pages before importing. A thumbnail is not enough to verify a subject. Check the creator and usage conditions, and prefer a source that explains what is depicted.
Review the result
If the result is wrong, change the query rather than accepting the first attractive image. Keep the scene marked as missing material until an appropriate asset is available.