The average hiring manager spends less than 30 seconds on a cover letter before deciding to read on or move on. Most cover letters never make it past those 30 seconds because they commit the same predictable mistakes. Here are the five most common — and what to do instead.

Mistake #1: The Generic Opener

"I am writing to express my interest in the Software Engineer position at Acme Corp." This sentence appears in thousands of cover letters every day. It says nothing. The hiring manager already knows you're interested — you applied. A generic opener is a wasted line that signals low effort.

Fix: Lead with a sharp, specific statement about why this role or company matters to you — or open directly with a relevant achievement. "After three years building payment APIs that processed over $2B in transactions, I'm excited to bring that depth to Acme's fintech platform" is impossible to skim past.

Mistake #2: No Numbers

Cover letters that only use vague language ("contributed to," "helped improve," "was responsible for") fail to convey actual impact. Quantifiable achievements are the clearest signal of competence.

Fix: Anchor at least two claims in numbers. Reduced deployment time by 40%. Grew monthly active users from 12k to 85k. Cut customer support tickets by 30% through self-serve tooling. If you don't have exact numbers, use ranges or comparisons.

Mistake #3: Copying the Job Description

Restating the job requirements back to the employer ("You are looking for someone with strong communication skills and experience in Python — I have both") reads as lazy and fails to differentiate you from anyone else who applied.

Fix: Don't describe what they want — demonstrate that you already do it. Tell the story of a specific time you did the thing the job description asks for.

Mistake #4: Making It About You, Not Them

"This role would be a great opportunity for me to grow my skills in X." Nobody cares. Hiring managers are solving a problem, not running a training program. Every sentence in your cover letter should answer one question: what problem do you solve for them?

Fix: Frame your value in terms of their goals. Research the company and reference a specific challenge, product, or initiative. Show that you understand their world, not just your own resume.

Mistake #5: No Clear Call to Action

Ending with "I look forward to hearing from you" is forgettable. Passive closers leave the reader with nothing to act on.

Fix: Close with a confident, specific statement. "I'd welcome 30 minutes to walk through how I approached [specific challenge relevant to their role]." Specificity signals intent and makes it easy for a recruiter to forward your letter.

A Framework That Gets It Right Every Time

Writing a great cover letter isn't about finding the perfect words from scratch — it's about having the right structure to plug your experience into. The Cover Letter Pack — All Industries includes battle-tested templates built around this exact framework: a sharp hook, quantified proof, company-specific relevance, and a confident close. Five formats, one for every situation.