The most common problem with job application letters is that they become a data-dump. Applicants describe where they have been and what they have done and leave it to the employers to work out what is relevant to their needs.
The message appears to be, “Here it is. I don’t have time to sort it out, so work your way through it, and if you are lucky you will find something that is useful to you.” Sounds hard, but that is what most applicants do, and it won’t work!
It is the applicant’s job to look closely at the employing organisation and see what they are on about and which of the many skills and experiences they have, will interest the employer.
Just listing your work history is not enough.
Read the job advertisement, the job description, any duty statement or outcome statement or anything that will tell you what the employer needs in an employee.
Think of any job as a problem and ask yourself what you have that would solve that problem; what skills, knowledge or experience can you apply to that problem.
For example, it is not good enough simply to say that when you worked at xxx you have experience in developing websites. You must then explain how that experience gave you the skills to design the websites in the position offered.
The only thing employers are interested in is what you can do for them.
The golden rule: Offer no information unless you can state clearly how it will benefit that particular organisation.
So be very selective in your letter writing and never use the same old letter again and again.