* Knowledge: know the craft, know what you are doing, don't trade on assumption.
* Know how to control your emotions: it's very important that you know how to control your emotions like fear and greed in trading.
* Know how to manage your risk: knowledge and emotional control gives you money, but proper risk management skill protect your money and your gains
Learning never ends and so to be more successful and profitable in every areas one find themselves adopting the strategy of being informed matters a lot. Just as the saying goes " if you're not informed you're deformed". Seriously an investment in knowledge pays a whole lot and most times people neglect this fact and venture into things cause they want to make money faster, but along the line they get a hit back this is the most reason people fail in trading.
Sure, learning don't used to ends because every day we learn new things and have experience to do what will bring profit. Trading is something that is unpredictable we can be wining anytime you most have bad day that will make you lose alot of funds when trading. All what op mentions is good and that will minimise your risk and won't make you lose mostly but he can't stop you losing if the market is bad because is unpredictable that is why most people call it gambling. And I can says trading is not lucky you need to have the knowledge and skills or experience first before you can achieve your goal on trading.