The skill is stating the relationship precisely. 'A physician practices medicine' is vague; 'a physician is a licensed practitioner whose field is medicine' is sharp, and the sharp version makes it obvious that 'attorney : law' fits while 'attorney : courtroom' (practitioner to workplace, a different relation) doesn't. Vague summaries let the wrong answer slip through; precise ones expose it.
A few relation types recur: part-to-whole, category-to-example, cause-and-effect, degree, and opposite. Knowing the category doesn't solve the puzzle, but it speeds the search. Watch for options that share a surface link but flunk the precise relational test. For how this connects to bigger analogical reasoning, see the Analogical Reasoning category.