How do I know if I am a competitive applicant for a top/second-tier grad school? I am contemplating on applying grad school, both MS and PhD, in Computational Social Science, such as Computational Analytics and Public Policy at University of Chicago. 

But I am not sure what kind of applicant I am. How competitive or desirable I am as an applicant for a grad school. I am worried if I target wrong schools, too high or too low. Of course, I know that ranking is not everything, but at the same time, I don't want to make any mistake, such as failing to evaluate myself.

I think my profile is quite unique and interesting, but not sure if it would attract attention of admission committees. I have been always passionate about working for abused children. But how? Firstly, I was interested in Corporate Social Responsibility, then in Child Psychology, in Social Work, and now in approaching social issues by using computational methods—Computational Social Science.

I did my bachelors in Business Administration(GPA 3.4/4.0) in Korea and partially in France, and did my master of social work(GPA3.9/4.0, full-tuition scholarship) in Australia. All are highly ranked schools.

My GRE score is V:151, Q: 170, AWA: 4.5. I have a range of research experiences in psychology, Social Work, and Information Technology(total 6 labs, from 3months to 1 year). I will have 1-2 papers published by the time of submitting my application. The research will be about improving the lives of international students in my department. I have earned bursary($2,000) for this pilot project, which will be implemented in our department from next year. 

I dropped out of middle school in Korea and went to the US by myself when I was 15. I wanted to see the bigger world. Then I came back to Korea and taught myself to get into a Uni. After completing my BA. I worked two years as a Sales Channel manager at Samsung Electronics managing $6 million per year. But I soon realised that doing CSR in Korea is too unrealistic. Then, I quit and gave all my savings to my parents (you know, there is high expectation on children by their parents in Asian culture), and went to Canada to find a way to work for children. After participating in several studies in Toronto, I decided to study social work and went to Australia to do MSW. 

I also have a long list of volunteer work, mostly working for children and their family. And I have been making my living working in restaurants since I quit my lucrative Sales manager position at Samsung. 

I wonder if my profile would make sense to grad program admission committee, and would like to know how I can make it more attractive. I have been thinking about paying some money ($300/h) to do a consultation for admission. Do you think it is worth it? I want to know how competitive applicant I am.
There is one thing that comes across clearly to me based only upon what you've written. I believe you are a very hard worker and you are willing to take risks. These two characteristics are very attractive to many people.

I think you need to concentrate on writing a succinct (but complete) résumé that showcases all of your accomplishments and evidence of positive character traits. To answer your main question, I already have a clear sense that you are definitely competitive. Your GPAs have shown an increase over time and you have a unique history. This means you also have a unique perspective on life.

If you spend money on anything, you'd probably get the most bang for your buck if you had a professional write your résumé. Then, you could make edits to that to suit your own personality. Get that done quickly and then start applying to lots of schools. Don't spend any more time worrying about whether or not you're competitive. You are. Stop worrying about making mistakes. This isn't life or death, it's simply grad school. Just make sure that spending money on grad school will actually amortize in a reasonable amount of time. I think it will definitely do so for you based on the avenue you are interested in pursuing.