I would add here the ability to learn. Time and practice are really important, but what is the sense in practice if you don't learn from your mistakes? Many people may spend different amount of time on learning how to trade and this amount, from my perspective, depends on learning abilities and the way a person deals with losses.
Time and practice are the key points in trading activity. I would add here learning of theory, because it also matters a lot on initial stages. To my mind, the more time you dedicate to trading activity, the more impact you will have in future, because time will be transformed into an experience. Nevertheless, you have to stay focused on the process and try not to distract on time, because once you won't be able to dedicate time to trading and you will be stressful, because you promised yourself to trade as much as you can. Anyway, everything goes step by step. You won't even notice first steps in trading.