Pretty straightforward achievement, score 50 goals in your Rookie season in the NHL. One thing that might be helpful to some, is that you can change the sliders as much as you want to help you out, and the achievement will still unlock.
Setting your shot accuracy and power to 100% and the AI Goalkeeping to 0% makes this one pretty easy if you want to put in the time to score 50 goals. You obviously wont score on every shot, but it will certainly make this a lot easier. You can change as many sliders as you want without voiding the achievement.