Understand a chengyu
Choose the modern meaning. Do not over-focus on the literal story yet.
画蛇添足
画蛇添足画蛇添足
huà shé tiān zú
to ruin something by overdoing it
Why this works: Chengyu compresses a whole situation into four characters. Learn the use case first; the old story can come after. Match the chengyu to a modern situation first, or it becomes decorative trivia.
Common trap: Do not translate one Hanzi at a time. The answer is the meaning of the full sentence, including word order and context. A chengyu is not a random four-character sticker. It needs the right situation or it sounds forced.