I was unemployed and job hunting for 1½ years. The application and interview process is ridiculously demoralizing.
My main conclusion I came to is that hardly anyone is skilled at hiring. It’s like a an afterthought and distraction from their primary competencies at work. They don’t know what to ask for, how to ask for it, or how to know if they’re getting what they asked for. I understand how it feels, but don’t let their incompetence get you down if you can help it.
In the end, I think the two biggest factors in getting hired is who you know that can give you an in, and just plain luck you’ll connect with someone who perceives you as an asset. There is almost nothing you can do about either of these. The rest of what you can do might boost your prospects a bit, but not much. But you’ve got to do them anyway.