I have done MSc in Quantum Field Theory and want to apply to the US for graduate studies, i.e. a PhD. Since the country I come from, Theory is not very popular, and research is usually done before PhD and nit before it, I don't have any research experience. I have done a project though, on quantization of non-linear fields by non-perturbative methods. And am currently doing a project on conserved quantities in guage theories and massive gravity. Now the problem is I'm clueless about what to write in my SoP. Since I'm required to state my research goals and interests and my ideas for research. I'm interested in Theoretical Physics, mainly in String Theory, Quantum Field Theory and Quantum Gravity. But beyond this, I can't elaborate on what specifically inside these topics would I like to pursue. So the following are my doubts: 1) How to convince them that I'm prepared for carrying out research? What do I mention? 2) Why do I need to prepare different SoPs for different institutions and how do I do it? Since my interests will remain unchanged regardless of the institution. 3) What do I state my research goals or areas of interest as? Because it's not going beyond one line, i.e. a sentence simply stating my areas of interest. Anything else? Any other tips? I'm almost desperate. Any help would be highly appreciated.