In my line of work (recruiting, job search coaching, and resume writing) and through my comments on Reddit, I'm often asked by job seekers how they can get noticed by a favored employer (which we'll call COMPANY). A good resume, cover letter, and online profile are the standards if you don't already have a friend on the inside, but when competing with candidates who might look better on paper, your results might not always be positive.
When you have narrowed a job search down to a few top places where you really want to interview and perhaps your qualifications fall a bit short of the company's ideal candidate, a bit of extra customized effort can make a major difference in your results. Most people tend to use elaborate cover letters or resume delivery methods, which may work sometimes but aren't entirely original. Sending a box of cookies with a hidden resume inside might get some attention, but methods like this don't elevate you as a candidate so much as they make you appear willing to bribe.
Your mileage may vary (read: good luck!) when it comes to the biggest names that get hundreds of thousands of resumes per year, but startups and smaller firms will find one tactic difficult to dismiss or ignore.
What's the most effective way in?
Use COMPANY's Stuff!
If you want COMPANY to say yes to the interview, create a project using COMPANY stuff. This could be APIs and data sets, open-source code, or anything resembling the development work you might be doing while working for COMPANY.
Does COMPANY have some publicly available APIs? Create a project that makes some novel use of the API or extends the functionality of an existing related project. Find some public data sets that pertain to COMPANY's business and create something with them using the tech stack COMPANY lists on their job specs.
Is COMPANY involved in open source? Jump into a couple of their repos and see if you can address a few of their issues.
Read up on COMPANY's tech blog, find out what the developers are working on and any unique challenges they faced, and make a comment linking to relevant information.
It's a pretty simple concept. If you are applying for a job with COMPANY, anything you provide that reflects the kind of work you'd be doing for COMPANY serves two purposes. First, this is perhaps the best possible evidence of your work quality using their tools, and second, it demonstrates your interest in and potential commitment to their work.