Unfortunately no matter how many good moves you make you can still lose to just plain bad luck. Every fantasy football player will come to this at some point and it can be really frustrating. This past week I was tied with my opponent, I still had my QB left to play and he had nothing. I needed 1 point, just 25 yards or a touchdown. Jay Cutler ended up getting -3 points for me, which is unheard of. It hurt, because I thought I did all the right moves, but sometimes you just lose to bad luck.
This is a fantasy game, so we don't have actual control of what players do. This is pretty obvious though. Thats why if you if take part in this hobby, make sure you take everything with a grain of salt. Understand that you will have good luck and bad luck, over a long period of time it will even out. In order to win though over time, you need to make consistently good moves week to week.