There is nothing like a ‘strong’ SOP. Your SOP is a very personal document that you use to convince the admissions committee (adcom) of your preparedness for the course. It can highlight your research works, achievements, strengths and, in the process, bring out your personality. PLEASE MAKE THE FIRST DRAFT WITHOUT LOOKING AT ANY OTHER SOP. Just highlight your interests, achievements, goals and link them. That’s all there is to a good SOP.