Probably the three biggest takeaways I have from my own experience:
If the company is big enough to have an HR department, it is going to be hard to get hired as a non-standard applicant. Too many people would have to agree to take the risk, and HR is NOT about risk taking.
Some type of personal connection is extremely important. Meeting someone at a job fair/meetup/hackathon/whatever is going to get much better results than emailing a resume.
Recruiters are probably not going to be of much help. Companies do not want to pay recruiters commissions for jr devs.