Joining a professional organization, even when you're still a student, can enhance your education. Professional organizations provide networking opportunities, a glimpse of the profession, and a chance to meet a mentor. Many publish trade publications that offer a window on the most current aspects of your potential career. Some even offer scholarships!
Read more in Why join a professional organization?
Some other resources (far from comprehensive):
A resume and cover letter are your introduction tools to an employer. You are marketing yourself. Like a brand, you want to promote your experiences, skills, and accomplishments that relate to the job to which you’re applying to show why you are a perfect fit for the company. This is an art; there are many opinions and trends about how to be successful at writing a resume and cover letter. Understand the basics, and then get creative.