Job Hunting – How to get your resume seen by a human?

I'm specifically asking about applying through job boards or through the "careers" portal on company websites in the US. I get a fair amount of interest from startups by posting here in the monthly "Who wants to be hired?" thread, but a month is a long time to wait when a job has become intolerable.

Any tips for beating ATS resume filters?

I skip and leave blank any section in a job application form that asks for information that's included in my resume like "work experience". Does skipping these invoke the ire of the ATS?

I also skip any demographic/disability/veteran status questions or choose "decline to answer". I assume there are serious legal strictures against taking those into consideration when evaluating a candidate.

How important is a cover letter? Is a two or three-sentence cover letter sufficient? necessary?

General online job hunting tips?