Follow up/second email

I am currently a freshman at a target undergrad and feel like I have reached a far enough point in the school year that I could reach out to the connects that I made from a summer gig at the headquarters store at a fortune 500 company. I have reached out to these people once before, so this is going to be more of a follow up/update email. However, I am struggling with where to start in the email. I know that the majority of the email is going to be me talking about my experience at school and the organizations that I've gotten involved in etc. But I don't want the email to be just about me. I also want to ask the person that I am emailing how they have been doing, what's new and evolving at the company etc. I am just unsure with how to set all this up and what I should put as the subject.