How do you know where you stand among applicants?

Honestly, I wouldn't even try to stress this and guess this. What you are possibly missing is that hiring is a lot more about finding the person with the right  "fit" for the firm and job, and "skills" and even "experience" are just some of the considerations. You may be perceived as the better fit due to your personality and time spent at some random activity (e.g. playing college football or whatever) as that fits the nature of the team/firm. You may also have some unique skill or experience that you think has little value but the firm may be actively considering doing deals in that space (but they can't tell you for confidentiality reasons). 

Once you are past college recruiting, which can be more of a beauty contest with few dimensions (GPA, school, major, and internship experience), then it comes down to far more intangible elements to be honest. This is incredibly true for senior leadership hires. Hard skills matter less, soft skills matter more. Where you went to college goes close to zero in value, etc. 

With all that said.... I'll give one "tip" or item to focus on for the "senior analyst/associate level".... that is.... "can this person be seen as likely for promotion", I think you will not have to worry about your "raw skill" if you have a few years of legit experience. The firm will want you for your leadership/growth potential at that point, far more than rote analyst/modeling skills. So poise, speaking, presentation skills, breadth of knowledge of the industry, and even size/scope of network all start to factor more favorably. Demonstrated leadership (whether at the job/on deals or even in organizations like NAIOP) can be the killer point to differentiate yourself at this level. 

Also, will say this, if you are just a analyst with 1-2 years of experience, I wouldn't oversell the "deals" you've done. No one is likely to think you were the rainmaker (nor expect it), be real about how you frame your experience, people are not stupid. 

Also allongo is quite correct, your best strategy is going in like you deserve the job. They selected your resume for interview, so you can safely assume your prior experience, schooling, and general presentation passed the test. Going in as if you are unsure of your qualifications will only cause them to doubt you and substantially reduce your chance of future rounds or final selection!