When you face the "job market" after many years of being unable to work for many years. It can seem daunting. However there are some things you can do to ensure a better application.

Re-draft your Curriculum Vitae (CV), you may find it useful to include two statements. One briefly about you and what you offer/your goals generally "i.e. I am an ambitious extrovert .....".  You may also find it useful to draft a concise, one page, summary of your CV commonly referred to as a "Resume".

I am often surprised when I proffer advice to friends that they find describing "Interests & Hobbies" difficult often just listing very typical options. On reviewing a CV for a friend they had noted "horse riding" as an interest with nothing more. We discussed this, and I even found out more about my friend. Suffice to say they expanded on this hobby to include awards won etc. They were short-listed and interviewed.  Most of the interview was about what had been written about their "horse riding".  In putting a little more information this person was actually demonstrating and saying "I am competitive, I am used to winning and losing, I am able to accept criticism and make the effort to improve upon my weaknesses".  They also secured the job.

It is important to try and make your CV standout. Once a recruiter has established you have the qualifications & experience required (the same as everyone else that maybe shortlisted) they then turn to the more personal information. This is the area in which to set yourself apart.

Get a few friends or family members to revise your CV. They may find things such as spelling mistakes that you have missed. They may also give you some good advice on improving it. 

Regularly revise your CV yourself. If you have not been getting called for interview, change your CV. It maybe you are not giving enough emphasis to your key skills or in places you may be vague or "waffling".

It is often the case you will be given a Job Specification and, becoming increasing common, a Person Specification. 

A Person Specification defines the person needed for the job. There will be Essential Skills and maybe Desirable Skills. You need to meet the Essential Skills and demonstrate that you do.  They also tell you how to tailor your application. 

For example if an Essential Skill for a job with a HIV Charity was "Understanding of current HIV antiretroviral therapies". To support this with "I am HIV+ and take them everyday" isn't sufficient. If however you say in your CV that you "volunteered for organisation X for two years where you advised patients on treatment options, adherence issues etc" the requirement is begining to be more sufficiently met. You have demonstrated your experience and of course any employer could ask "organisation X" for a reference. A crude example but I hope it makes the point.

I would also draw your attention to the Disability Discrimination Act as it applies to what you can disclose to a potential employer and how they must treat you.

Remember your application needs to clearly communicate how you meet the skills being asked for.  If someone has 1000 applications to assess it will be those that are easy that will certainly go forward. Be concise, support with facts and get advice (there is loads on the Internet).

I hope this helps and feel free to comment with advice especially if you have "recruiting" experience.

Below are some links to other sites that offer some more advice.

For writing a CV.

Reed.co.uk

CVtips

About.com

BBC 

For more information on Person Specifications.

tutor2u.net

Wikipedia

Department for Business Innovation & Skills

Business Link

Current Vacancy pages for HIV Sector Charities.

Terrence Higgins Trust.

National Aids Trust.