Start by practising "stop and think" when dummy comes down. Always give yourself at least 30 seconds to think about how the play might go — which suits you plan to play, and why. Through experience we learn to spot dangers and opportunities before it's too late, but the key skill is built through routine: develop a habit of planning, and an awareness that playing too quickly without a plan — particularly at trick 1 — can be very costly.
"Take your time at trick 1 and make a plan — even a mediocre plan is a good start."