There are a lot of considerations that go into hiring anybody. It represents a substantial investment by the company. At my job, it takes over 6 months of intensive one on one training before the employee is qualified to do the job.
I am the supervisor, I do the interviews and the hiring. The first thing I look at is the application and resume. I look for spelling errors, bad syntax, and poor grammar because the job entails a lot of writing so those skills are desirable.
Next I look at the work history. I look to see if the jobs held were comparable to the job they would be taking. I look at the length of time spent at each job, the duties performed, and why they left.
I do check references.
If there is a period of unemployment, I look for a reason. It isn't an automatic out, but if there are no reasons besides "nobody wants to hire somebody of my race/creed/sex age etc." that would be a disqualifier.
The last employee I hired had been out of work for 2 years because of a workplace accident that left him with limited mobility.
He had sterling qualifications, and over the past 9 months has shown himself to be dependable, conscientious, willing to learn and accept responsibility, very open and friendly to other employees, in other words a real asset.
His limited mobility was difficult for most jobs, but working at a computer console, he uses his mind and is as good as anybody.
As an employer, I try to determine the best fit for the job and culture of the business. If the person has the best qualifications for the job, even if they have been out of work for a while, if there is a valid reason for it, I am happy to give them a chance.
I have found that in some cases, those that have a hard time finding work through no fault of their own, can be the most loyal and dedicated people I have.
If you have been out of work for a while, but are getting interviews, if you don't get the job, ask the interviewer if they will give you some pointers. Maybe you need to work on your writing skills, or polish your resume. Maybe you need to work on your interview skills, eye contact, being engaged and alert, having knowledge of what the company does, asking about specific duties you would be performing, all of these can impact the impression you make.
If you remember the person doing the hiring has a responsibility to the company to find the best person for the job, throw all the self pity and prejudices out the window, concentrate on making yourself the best candidate, have real reasons for being out of work for an extended period, and you may be surprised with that job you have been looking for.
The effort you put into getting hired will reflect well on you and give the interviewer something so that he can feel good about taking a chance on you.
Remember, they are trying to find the person that will perform the best in that job for the company. There is very little personality involved unless you are disrespectful, or the first question you ask is about vacations and sick days.
There are a lot of red flags that employers have, and you may not know what they are, but if you put forth a good faith effort, you can score interviews, and if you score interviews, you have a good shot if you have the skills to impress the person/s you are addressing in the interview.
Who knows? You may find you are employable after all