There is no definitive answer to this question as everyone has different interests and opinions. However, some possible topics that could be interesting to many people are:
-How to be more successful in life
-How to be happier in life
-How to make friends easily
-How to overcome shyness
-How to improve your memory
-How to be more confident
-How to get over your fear of public speaking
-How to deal with stress
-How to achieve your goals
-How to be more organized
-How to be more productive