Trading works on the same principle as begging. Find an intersection that looks like it’s in a wealthy neighborhood, squat down with a bowl in front of you, and if someone tosses you some money, stay a while. But if a rich person sends a dog to bite you, run—fast. Never hold on to a losing trade: at best, you’ll get bitten (lose your principal); at worst, you’ll be mauled to death (get liquidated). As for knowing which neighborhoods are wealthy, you’ll need to learn a bit of feng shui (trading strategies). If you can never find one, maybe you just weren’t born lucky.