One of my few skills is the ability to quickly and accurately decide whether applicants for jobs are worth interviewing. I have a simple A, B and C classification system. If you don't have any of the applicable skills, you're a C. If you have some skills, or in some way indicate that we can train you, you're a B. If you have a lot of skills and have done the research to write competently about what the organization does and how much you support the goals of the organization, you're on the interview list.
And unlike some companies and organizations, I actually read all of the cover letters and resumes. Using buzzwords won't get you an interview, and neither will telling me that you're a bundle of energy. (My teeth hurt at the very thought.) But there are a bunch of other things that will get you put in the C pile. First, proofread your cover letter and resume. That means reading the damn thing, and correcting any misspelled words, improperly placed punctuation, and sentence fragments and run-ons. If the first sentence of your cover letter is a fragment, it had better be a really good one. And the comma splice is not used in American English, so unless your resume says you went to Leeds, a comma splice should appear nowhere in your letter.
Don't make me decipher your resume. Tell me where you worked, when you worked there, and what you did. The "skills-based resume" is hard to follow, and I'm going to figure out any gaps in employment anyway. Don't try to confuse me.
Read the instructions carefully, and follow them exactly. This is particularly important if "attention to detail" is one of the job requirements. If we want email only, don't send us hard copy. I, for instance, work remotely, and a hard-copy submission is hard for us to deal with. Don't ever send anything in a format that's difficult or impossible to open. You're a C if I can't open your documents. If I want a PDF, send a PDF. If I want a Word document, send me a Word document. If you can't send in the required format, I should know why.
Finally, no matter what the resume "professionals" tell you, do not telephone us if we ask that you not telephone. It brings you to our attention, but not in a good way. And I have never had anyone telephone who hadn't already been relegated to the Cs.