At a certain point, how well you do your work ceases to matter. It's like, you have finished level one and you're ready for level two. Level two is played with different rules. What helped you pass first level -- doing your job well -- still remains important, but that's not going to help you pass the second level. Finding good opportunities is the key in second level. Engaging yourself in 'critical' assignments is an important thing you should do to keep your place in the game.
Also, no one tells you when you are promoted to the next level.