What should be the best answer for " According to you ,what are the things you lack the most and how do you plan to improve it?"

This is a question of self awareness. The interviewer wants to find out whether you are aware of your weaknesses or not. You need to play down whatever weakness you have & also indicate what actions you have taken to overcome these. For example if you are shy or an introvert you could say that I sometimes take more time in mixing around with people & have started taking part in group activities.This has helped me to make new friends & overcome my shyness to a great  extent.

always try to learn from your previous experience regardless in which you lack the most, depends on you either you want to be a pilot or as passenger.

No person can term himself perfect.Everyone tries his level best to make the best plan  to rise to the best level in life.When these plans click with just zero point one percent of luck,the achievements are tremendous.Those who do not take risk to cash upon opportunities they are unsuccessful. Opportunity never knocks the door second time.Whenever you get chance take risk you will surely b successful. 

I focus on communication management most of the time. Whatever we do, communication (RACI) plays an important role in an individual's success and then followed by the team's success and then larger entities.

For me , As an IT manger for more than10 years , i am always try to find a place to have a Certified courses ,ex: CCNA MCITP .... , unfortunately its hard in my city .