To improve your critical thinking skills, you need to PRACTICE a lot. Practice more and more. Keep solving sums and numericals, keep attempting varied questions, and surely with time your thinking skills and analysis will go on improving and increasing. Also to improve your personality and life thinking skills, you need to experience and learn more and more from all the incidents of life and one of the best ways to do it is the SWOT analysis.

In the end of every day, note down all your Strenghts, Weaknesses, Opportunites (in future) and Threats ie the SWOT analysis. By this, you can actually work on improving your personality, to have a better perception of your life and weith time, yoou develop a lot of maturity.

Best wishes. Thank you.