Mahendra Singh Dhoni is potentially one of the best captains in the history of not just Indian cricket, but also world cricket as a whole. While statistics don't lie when it comes to his success, as he is a contributor of both a batsman and a wicketkeeper, and Dhoni has also held the additional responsibility of captaincy for club and country across all 3 formats and has done so with calmness.
Dhoni is a picture of composure, no matter what the team finds itself in, also his composure and level-headed thinking even under severe pressure has been invaluable for India.
The prime factor for his calm nature is that he believes and has stated that he focuses on process rather than the results. However, when Dhoni faced any particular pressure situation, he doesn't think about the results and puts all his concentration on improving the process.
MS Dhoni is an epitome of confidence which is explained by an incident that reflects his self-belief that is: he promoted himself instead of Yuvraj Singh in the World Cup Final 2011 final against Sri Lanka because his confidence goes beyond his batting. Secondly, he put his faith in a Joginder Sharma to bowl the final over in the T20 World Cup 2007 Final.
It is believe that MS Dhoni was not brought into the Indian cricket team for nothing, as he had tonnes of runs in his first class career and has continued to do the same in his international career as well. He is well known as the best finisher of the Indian cricket team as of now.