Not having a clear plan, not being consistent with your practice, and only playing what you know over and over again. These are three very common mistakes and this video lesson shows you how to combat them.
For the practice checklist mentioned in the video, go here.
For a load of essential things for bass players to know, go here.
Here's another useful post: How To Develop And Keep A Music Practice Routine.
Don't underestimate how important the habit of practising well is. It's the key to you reaching the peak of your potential.