I agree with @FatAgainItsLettuceTime about the automated sifting and the importance of showing that your CV matches the job specification.
My husband was in this position and was sometimes getting rejections within 10 minutes which began "we have studied your application carefully", erm, yeah right. He thought he wasn't getting through automatic filters, perhaps based on which university applicants have attended, or having done a specific course.
I asked my HR manager for advice on behalf of my husband on this point and she said:
"It depends on the business [whether the CV is read by a human or not]. Here, for example, every CV is read by a human being; however, in 99% of cases we don't spend more than a minute looking at the CV at the pre-selection stage. That means it needs to include key words from the job specification to ensure that the person who may have hundreds of CVs to read can evaluate in a matter of seconds whether the applicant's profile matches the job or not."
For all his future applications my husband went through the job specification and identified all the key words and made sure they were given a prominent position in his CV, so that a human reading his CV would spot them immediately or a computer programme reading his CV would pick up on them.
He also adopted another technique, which might sound a bit weird. In his case, he was looking for his first civilian job after coming out of the army, which meant that although he had lots of great professional experience and transferable skills, his CV often wasn't a perfect match for the role, or he was up against people from the top business schools who had little professional experience but the right university name and qualification on their CV. What he did was this: after including all the key words on his CV corresponding to skills and experience he did actually have, he typed in all the key words he could think of corresponding to skills and experience he didn't have and couldn't reasonably claim to have, put them in a really small font and coloured them in white. He then converted his CV to a readable PDF before sending it. The logic here is that if the pre-selection is done by a computer programme rather than by a person, including things you don't have on your CV but making it invisible to the human eye increases the likelihood of your CV making it through to the next stage of the process where it is actually read by a person. This wouldn't have made a difference for the job he ended up getting because in that case the job ad gave the hiring manager's email address so he was able to send his CV directly, but perhaps it might help you or someone else reading this.
He was also advised to put the title of the job he was applying for in the first line of his CV or in the document title.
The other thing that I think might have made a difference is in the covering letter. He and I had an argument a while back because I read his covering letter and it was like a carbon copy of letters he'd done for completely different roles at different companies. I said that upon reading the letter it wasn't at all obvious to me that he understood what the job was or what the company does. Lots of no-hopers will apply for jobs they aren't remotely suited to and recruiters will spend days sifting through all this dross. Yours needs to stand out as being a serious application from a serious candidate. It might seem stupid and weird to say in the covering letter what the job is and what the company does - they know what the job is and what they do, after all - but you need to demonstrate that YOU know both these things.
By the end he was starting covering letters something like, "As a former army office with ten years' experience managing military operations in conflict zones, this role as project manager working with clients in the defence sector represents the ideal opportunity for me to use my existing skills in a new context." So in that first line he'd said who he was, what the job was, and why he was a good fit.
And then elsewhere in the letter he would put something like, "As a previous user of military mapping software, I have a particular interest in the kind of technologies being developed by [company], and am ideally positioned to give an insider's view on how best to promote [company's] products to potential clients." In this line he shows that he understands what the company does and says how he could play a role in that.