The job application process is no doubt tedious and tiring for everyone. We've all been there - sifting through the various job ad postings, sending through resume after resume, and all we want to do is get the application process over with as fast as possible. Everyone tells you to at least take a few minutes to tailor your resume and cover letter to each job you apply for.
Personalizing your application materials no doubt increases your chances of getting a call back, but I'm also going to let you know that there is another way to increase your chances at getting that interview call, and it has absolutely nothing to do with who you are or with the quality of your resume and cover letter - it simply has to do with when you send through your materials.
I recently had a friend complain to me about getting no call backs at all. She had sent through personalized resumes and cover letters dozens of times and had not received one interview invitation. Sure, the job market is extremely tough in some areas at the moment, but to receive zero phone calls out of dozens was a bit alarming to me.
I asked her to show me her resume, and everything looked great. She told me about the sites she was applying through, and I saw no problem with that either. But she then told me about the application process itself, and this is where an important detail stood out - the time she was sending through her resumes.
Many job seekers, especially the already employed, use nights and weekends to send out the bulk of their applications, and this can sometimes put them at an immediate disadvantage. Anyone who's worked in an office environment knows that Mondays are usually extremely hectic. Everyone's trying to catch up on their emails and phone calls, and there usually isn't a lot of time to spare, especially on things that are not urgent, like reading resumes. The first thing most people do when reading emails is prioritize and figure out what needs to get done sooner rather than later - resumes, especially ones sent days ago, usually fall into the later pile.
The point is that you want to be sure that your resume and cover letter are noticed. Sending them through on the weekend not only puts your email toward the back of the line chronologically, but it also puts it among the spam messages that have filled up the inbox, and you don't want to accidentally get deleted.
Ideally, try to respond to job advertisements during the day, when someone is most likely to see it, let alone read it. If your only time to apply for jobs is on the weekend, at least try to send through your cover letters and resumes toward the later part of the weekend, preferably on Sunday evenings. You want your resume and cover letter to be one of the first things the hiring manager sees, not something that they see toward the bottom of their inbox that they will get to later.