When you learn something new, strike while the iron is hot — practice right away.
Tips
memory
趁 (to take advantage of) + 热 (hot) + 打 (to strike/beat) + 铁 (iron). A blacksmith must hammer iron while it's still red-hot — once it cools, it becomes rigid and unworkable. This directly matches the English idiom 'strike while the iron is hot.'