Someone once told me that looking for a job, IS a full time job. And I believe this somewhat. You can spend days looking online for job openings. You can be as on top of it as they come--excellent resume, beautifully written cover letter, great references.....and still you wait by the phone, and nothing.
It's because in this business, it's all who you know. I can easily say that all of the cool, fun jobs I've gotten have been thru people I knew....either people I graduated with, friends from home who now live in LA, family friends, people I met thru internships, etc. I have gotten a few (let's say about 1 out of 100 submitted resumes) random calls, but they usually turn out to be for companies I've never heard of that don't seem to have much credence.
So in my humble opinion, you are far better off getting out of the house--go to a bar, volunteer at a homeless shelter, go join a squash game at your gym (squash seems very popular among the film crowd)--and MEETING people. I know often times you feel guilty, if you aren't forcing yourself to sit at the computer screen robotically submitting resumes, but you really really do have a greater chance of finding a job by putting yourself out there in LA.
Even if you do find a listing for your dream job online, your resume has a way higher chance of being read if you have someone in the industry submitting your resume and vouching FOR you. I know we all want to be proactive and feel like we are doing things on our own, but its a sad fact that nepotism is alive and well in Hollywood. So jump on that bandwagon and milk every contact you can!!!