LinkedIn is the industry standard for professional networking. Furthermore, over 93% of recruiters use LinkedIn as part of their recruiting practices. So if you don't have a strong LinkedIn profile, you risk losing out on both networking as well as employment opportunities. Below are useful resources to help you learn how to use LinkedIn effectively.
Have a current headshot where you are facing the camera and smiling
Update your headline with the keywords that represent your industry, function and personal brand.
Example: Brand Management | Retail | eCommerce
Your Summary section is where you introduce yourself and highlight the skills and experience you have honed and the value you bring to your organization or company.
List out each job experience and add in a few of your "greatest hits" related to the work - feel free to pull those from your resume.
Follow companies of interest, join groups and aim to have 500+ connections.
Best practices for key sections of your LinkedIn profile