Use the official traffic-control chapter
Work through the NY DMV chapter on traffic control and keep the manual open while you study signs, signals, and pavement markings.
Focus on what each sign or signal requires a driver to do, not only how it looks.
Practice recognition and decisions together
When you see a sign in practice, say the expected action out loud and then confirm it in the manual.
This connects visual recognition with the driving decision the sign is intended to support.