Your experience and qualifications might get you the interview, but your personality is what gets you the job. Employers look for people they think will be a good fit for the company - you're already expected to tick all the boxes for experience/qualifications. Make sure you've read the company profile, have questions to ask, are prepared to answer questions, etc. Also ask for feedback if you don't get the position.
Volunteering doesn't hurt either. I got my current job after volunteering for eight weeks. They decided they liked me, I'd learned how to use the system, and I was very interested. It was actually a full-time position that they let me have part-time. So yeah.