I'm sure you are all very familiar with the phrase "practice makes perfect".
I however, prefer a little twist on saying, as was once told to me by my very own piano teacher:

Practice makes permanent

The more you practice something, whether it be piano, violin or even football, the better you will become at it. However, if you are practicing mistakes, then you will become very good at those mistakes! The more you practice these mistakes, the harder it will be to correct them! So my advice for you, is to check that you are always playing the correct notes and using the correct fingers when practicing at home. If you do make a mistake, always be sure to go back and correct yourself!

Happy practicing!