The biggest difference I experienced in regards to responses to applications was when I've sent a personalised letter or email - instead of a generic one. So not "I'd like to apply for the position of team-leader, please accept my CV"
"I'm really interested in the position of team-leader you advertised in the Gazette last week as it's exactly the sort of work I enjoy and your company seems very progressive" etc. Actually make it sound like you wrote a personal, just for them letter.
The difference was immediate in the responses I got - even when they turned me down, at least they actually bothered to let me know they turned me down.