I have been trying to get a job for 6 months now and I keep getting reject after reject,mostly without an interview.
I have tried LinkedIn and applying to companies directly. After more than 500 applications and lots of iterations on the resume I am still nowhere.
What can I do to get a job ?
You are going to need to flip the script and proactively meet with people who might work at companies that you'd like to work at, way before an interview. To do that, you're going to need to put yourself out there. Sending resumes to a black box or "black hole" is not the best strategy for finding a job. Ask people to help you (professor, friends, students who might be better at job searching at your school). By being vulnerable, people will want to help you. (Note: This Ask HN is a good first step).
If you are not already attending tech meetups, consider moving to a location (not necessarily SF) that has meetups. If you are already attending tech meetups, start presenting at those meetups. Start organizing talks, maybe even a mini conference at your school. People who bring people together always have more opportunities than those who just show up.
Learn to talk to people so that you can learn about them and find what they need so they ask you what you need (in your case, a job opportunity).
Your goal is to become a local maximum, by being a host, organizer, or leader. It is near impossible to become a global maximum (e.g. president of a country) but you can easily become the leader/organizer of a conference or even a happy hour/coffee get together.
Consider a hackathon or two. If you do well enough, it is almost like a first job interview for the sponsoring companies. Also, it is a good test of "shipping something" and working under pressure with a team.
If you don't want to do this, at the very least sign up for an improv comedy class. I think this may help you get over your fear of messing up in person.
Without seeing your resume it is hard to highlight what you are doing wrong.
It is important to realize that your resume can get ignored for a variety of reasons. Typically the first filter is an automated system which looks for key words. Second a person in HR looks at it. For techies, the HR is a problem as HR does not look at things in a technical fashion... To get past HR, I recommend a resume writting service. Since at 500 applications you should get a bite, but there is obviously SOMETHING wrong with your resume.
<bitterness on> The annoying thing I have encountered is the companies (HR department) likes to FIND YOU! I have had calls from the HR department saying I would be perfect for a job at their company. I agree that is why I sent a resume last week. Radio silence follows. Implication being, what use is an HR department if they cannot find someone, they do not get as well rewarded if you find them.<bitterness off>
Have you considered visiting a recruiter? Since they are money orientated, they will work hard to fit your round peg in a square hole.
Keep it up, just broaden your search and keep getting more projects under your belt and adding them to your resume.