Suggestions For Efficient Practice:

1.   Listen to the whole piece

     You need to have an idea about what you are going to play. It is recommended to be inspired from a good performance. I repeat - just to be inspired!

2.   Use the self-observation during the practice time

     Be focused on your intonation, rhythm, sound, phrase etc. Stop and correct when it is necessary. Do not go further repeating over and over again the whole piece. It`s a waste of time!

3. Try also to practice slowly

     Going slowly allows you to attend more closely to errors creating a higher degree of precision.

4.   Take breaks 

     As a general rule, after one hour of practice take a break and rest for 10 minutes. 

5.    Ask for feedback  

     It is very important to have a feedback from a teacher or a mentor in order to improve, correct and strengthen your performance.

6. Read also this great articles:

    

    http://www.bulletproofmusician.com/how-many-hours-a-day-should-you-practice/

    http://www.essential-music-practice.com/efficient-practice.html

         http://tipsforclassicalmusicians.com/2012/11/16/musicians-guide-to-playing-fast/

As a conclusion, we need to practice and think about all the ways that could be done much better.     
  

Other suggestions are welcomed!