How to approach networking post graduation?

I’ve come to the realization that without networking, the likelihood of me landing any role is pretty slim. During undergrad, I had a job that allowed me to meet people. I even met some guy who worked in PE that was friendly and helpful but eventually lost touch…which I definitely regret now.

Now that it’s time to network again, I’m thinking of cold emailing & using Linkedin. How should I approach now that I graduated almost two years ago? I know it’s usually to network as a student but I don’t have that luxury anymore.