How can I Improve my problem solving skills using my mind only?
What is Mensa puzzles?Practice.
Complete your school work.
Do more than the assigned coursework.
Think about real life problems, and try to find logical solutions.
Work on stating answers and problems as precisely as you can.
Take a programming course, a encryption course, or an algorithms course (if available).
Try to solve problems here in the Physics Forum.
Read a Problem Solving Skills Book.
Try to teach yourself a subject.
Learn to play a musical instrument.
Try Mensa puzzles.