A good academic foundation of the basics in your field of interest is essential for graduate education.
Data collection experience is necessary. Make sure you collect data, analyze it, and make conclusions of the findings.
Practical experience translates into hands-on work in your field of interest and knowledge of what it requires.
Join a club that enhances the skills needed for your field: join an honor society and/or national organization.
Community service is a requirement for one to have a true understanding of a population and their needs.