The job boards make it too easy to...
The job search boards make it incredibly easy to apply the "wrong way". They all offer an easy apply button, or allow you to simply post your resume on their site, and allow employers to "find you". This is never the best way to apply. Please resist the urge to do this!
Customize your resume and target it to each and every position you apply for. This means, don't waste a lot of time creating the "perfect resume" before you even start your job search. What do I always say, "one cookie cutter resume will not get you the job".
When you find the job you wish to apply for, thoroughly review the job posting. They are giving you a very clear picture of the role and the type of person they are looking for. Ensure that your resume specific shows that you are the right person for that exact job.
Make it clear. No one is taking the time to infer or read between the lines. Include results, numbers, and accomplishments. Show where you have made a difference. You didn't just go through the motions of the job, you were damn good at what you did.