Economic climate? Redundancy? Lack of opportunity? Not qualified or qualified enough? Not applying for work that is suitable? Recruiters ignoring you? Applications being ignored or passed over? Picking the wrong job and then being made redundant again when the firm goes bottom up?
There are numerous answers to this question but only you know which are applicable to you and your circumstance. So what is preventing you from finding work? Take the time to think this over. You may want to make a list of what is and what is not preventing you from finding employment. Once you have done this, study it and consider what corrective steps you can take to address the issues. I can guarantee that you will need to make change and that will require increased effort.
Have you thought about looking at working for your previous employers competitors? Make a list of 20, 30, 40 or however many you wish and contact them all (make sure you know what you are going to say or have a framework of questions at the ready).
Do NOT rely on email. If you have unlimited time on your hands or are not concerned with being ignored then use email. Email should only be used for confirmation of a conversation or agreement as it can be a waste of time in the first instance. However, it can be used as a subtle back door tool if the gatekeeper will not let you talk to the decision maker.
Linkedin and social media: Research the names of the key people that could offer you employment and contact them through Linkedin.
If you are using a recruiter to find you work then ring them everyday for an update. If they avoid your calls then find another recruiter.
Just remember the idiom, when the going gets tough the tough get going and this applies to looking for work.