Slowly train your thoughts in decision making.. And like you've
mentioned in your other thread, you tends to think too much... Once
you've made up your mind on something, AVOID thinking much about it
UNLESS it's really necessary...
You can start 'practising' by doing some MCQ test of whatever kind
which may be of more relevance to your case... Set time limit for
the papers so that you don't have time to 'think extra'...